Apple II Plus Rev 7 RFI - Revision history

RMHenry: /* Kit Assembly */

2025-10-20T01:55:21Z

Kit Assembly

← Older revision		Revision as of 18:55, 19 October 2025
Line 59:		Line 59:
	File:Diode_Anatomy.svg\|Diode Markings\|link=https://wiki.reactivemicro.com/images/e/e9/Diode_Anatomy.svg		File:Diode_Anatomy.svg\|Diode Markings\|link=https://wiki.reactivemicro.com/images/e/e9/Diode_Anatomy.svg
	</gallery>		</gallery>

			* .001uF Ceramic Cap, 20%, 10v+, Z5R+ Radial-Disc-.250mil, C18-26, C28-53, 35 units total

			* .1uF Ceramic Cap, 20%, 10v+, Z5R+ Radial-.200mil, C4, C9-15, C54-86, C1, A1, 45 units total

Khaibitgfx at 21:53, 3 November 2022

2022-11-03T21:53:31Z

← Older revision		Revision as of 14:53, 3 November 2022
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	[[Image:IMG_20200206_085701304_HDR-Store-tiny.png\|thumb\|Apple II Plus Rev 7 RFI, Current Version\|link=https://wiki.reactivemicro.com/images/3/33/IMG_20200206_085701304_HDR1-Wiki-tiny.png]]		[[Image:IMG_20200206_085701304_HDR-Store-tiny.png\|thumb\|Apple II Plus Rev 7 RFI, Current Version\|link=https://wiki.reactivemicro.com/images/3/33/IMG_20200206_085701304_HDR1-Wiki-tiny.png]]

	The Apple II ''plus'' Rev 7 RFI motherboard replacement was started on April 20th, 2019 by Henry from [[ReActiveMicro]], and was officially released on February 15th, 2020. The 27-Series version of the ~~product~~ was officially released on April 1st, 2020.		The Apple II ''plus'' Rev 7 RFI motherboard replacement was started on April 20th, 2019 by Henry from [[ReActiveMicro]], and was officially released on February 15th, 2020. The 27-Series version of the motherboard was officially released on April 1st, 2020.

	This marks the first full computer product released by ReActiveMicro. The concept is a factory new replacement motherboard which is reliable and fully tested, to be used as a replacement for the original motherboard. This will allow the user a better experience and less issues moving forward. In contrast, most original motherboards now require constant maintenance in order to stay in a dependable running state. Compounding the situation, the original motherboard has low quality sockets, and old DRAMs and ICs which are power hungry and are well past their lifespan ratings.		This marks the first full computer product released by ReActiveMicro. The concept is a factory new replacement motherboard which is reliable and fully tested, to be used as a replacement for the original motherboard. This will allow the user a better experience and less issues moving forward. In contrast, most original motherboards now require constant maintenance in order to stay in a dependable running state. Compounding the situation, the original motherboard has low quality sockets, and old DRAMs and ICs which are power hungry and are well past their lifespan ratings.

Khaibitgfx at 21:52, 3 November 2022

2022-11-03T21:52:46Z

← Older revision		Revision as of 14:52, 3 November 2022
Line 4:		Line 4:
	[[Image:IMG_20200206_085701304_HDR-Store-tiny.png\|thumb\|Apple II Plus Rev 7 RFI, Current Version\|link=https://wiki.reactivemicro.com/images/3/33/IMG_20200206_085701304_HDR1-Wiki-tiny.png]]		[[Image:IMG_20200206_085701304_HDR-Store-tiny.png\|thumb\|Apple II Plus Rev 7 RFI, Current Version\|link=https://wiki.reactivemicro.com/images/3/33/IMG_20200206_085701304_HDR1-Wiki-tiny.png]]

	The Apple II ''plus'' Rev 7 RFI ~~project~~ was started on April 20th, 2019 by Henry from [[ReActiveMicro]], and was officially released on February 15th, 2020. The 27-Series version of the product was officially released on April 1st, 2020.		The Apple II ''plus'' Rev 7 RFI motherboard replacement was started on April 20th, 2019 by Henry from [[ReActiveMicro]], and was officially released on February 15th, 2020. The 27-Series version of the product was officially released on April 1st, 2020.

	This marks the first full computer product released by ReActiveMicro. The concept is a factory new replacement motherboard which is reliable and fully tested, to be used as a replacement for the original motherboard. This will allow the user a better experience and less issues moving forward. In contrast, most original motherboards now require constant maintenance in order to stay in a dependable running state. Compounding the situation, the original motherboard has low quality sockets, and old DRAMs and ICs which are power hungry and are well past their lifespan ratings.		This marks the first full computer product released by ReActiveMicro. The concept is a factory new replacement motherboard which is reliable and fully tested, to be used as a replacement for the original motherboard. This will allow the user a better experience and less issues moving forward. In contrast, most original motherboards now require constant maintenance in order to stay in a dependable running state. Compounding the situation, the original motherboard has low quality sockets, and old DRAMs and ICs which are power hungry and are well past their lifespan ratings.

Khaibitgfx at 21:49, 3 November 2022

2022-11-03T21:49:14Z

← Older revision		Revision as of 14:49, 3 November 2022
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	[[Image:IMG_20200206_085701304_HDR-Store-tiny.png\|thumb\|Apple II Plus Rev 7 RFI, Current Version\|link=https://wiki.reactivemicro.com/images/3/33/IMG_20200206_085701304_HDR1-Wiki-tiny.png]]		[[Image:IMG_20200206_085701304_HDR-Store-tiny.png\|thumb\|Apple II Plus Rev 7 RFI, Current Version\|link=https://wiki.reactivemicro.com/images/3/33/IMG_20200206_085701304_HDR1-Wiki-tiny.png]]

	The Apple II ''plus'' Rev 7 RFI project was started on April 20th, 2019 by Henry from [[ReActiveMicro]], and was officially released on February 15th, 2020. The 27-Series version of the ~~project~~ was officially released on April 1st, 2020.		The Apple II ''plus'' Rev 7 RFI project was started on April 20th, 2019 by Henry from [[ReActiveMicro]], and was officially released on February 15th, 2020. The 27-Series version of the product was officially released on April 1st, 2020.

	This marks the first full computer ~~project~~ released by ReActiveMicro. The concept is a replacement ~~board~~ which is ~~known good~~ and fully tested, to be used as a replacement for the original motherboard. This will allow the user a better experience and less issues moving forward. In contrast, most original motherboards now require constant maintenance in order to stay in a dependable running state. Compounding the situation, the original motherboard has low quality sockets, and old DRAMs and ICs which are power hungry and are well past their lifespan ratings.		This marks the first full computer product released by ReActiveMicro. The concept is a factory new replacement motherboard which is reliable and fully tested, to be used as a replacement for the original motherboard. This will allow the user a better experience and less issues moving forward. In contrast, most original motherboards now require constant maintenance in order to stay in a dependable running state. Compounding the situation, the original motherboard has low quality sockets, and old DRAMs and ICs which are power hungry and are well past their lifespan ratings.

RMHenry: Undo revision 6344 by RMHenry (talk)

2022-10-14T00:05:41Z

Undo revision 6344 by RMHenry (talk)

← Older revision		Revision as of 17:05, 13 October 2022
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	[[Image:IMG_20200206_085701304_HDR-Store-tiny.png\|thumb\|Apple ~~IIe Motherboard~~, Current Version\|link=https://wiki.reactivemicro.com/images/3/33/IMG_20200206_085701304_HDR1-Wiki-tiny.png]]		[[Image:IMG_20200206_085701304_HDR-Store-tiny.png\|thumb\|Apple II Plus Rev 7 RFI, Current Version\|link=https://wiki.reactivemicro.com/images/3/33/IMG_20200206_085701304_HDR1-Wiki-tiny.png]]

	The Apple II ''plus'' Rev 7 RFI project was started on April 20th, 2019 by Henry from [[ReActiveMicro]], and was officially released on February 15th, 2020. The 27-Series version of the project was officially released on April 1st, 2020.		The Apple II ''plus'' Rev 7 RFI project was started on April 20th, 2019 by Henry from [[ReActiveMicro]], and was officially released on February 15th, 2020. The 27-Series version of the project was officially released on April 1st, 2020.

RMHenry at 00:04, 14 October 2022

2022-10-14T00:04:56Z

← Older revision		Revision as of 17:04, 13 October 2022
Line 2:		Line 2:


	[[Image:IMG_20200206_085701304_HDR-Store-tiny.png\|thumb\|Apple ~~II Plus Rev 7 RFI~~, Current Version\|link=https://wiki.reactivemicro.com/images/3/33/IMG_20200206_085701304_HDR1-Wiki-tiny.png]]		[[Image:IMG_20200206_085701304_HDR-Store-tiny.png\|thumb\|Apple IIe Motherboard, Current Version\|link=https://wiki.reactivemicro.com/images/3/33/IMG_20200206_085701304_HDR1-Wiki-tiny.png]]

	The Apple II ''plus'' Rev 7 RFI project was started on April 20th, 2019 by Henry from [[ReActiveMicro]], and was officially released on February 15th, 2020. The 27-Series version of the project was officially released on April 1st, 2020.		The Apple II ''plus'' Rev 7 RFI project was started on April 20th, 2019 by Henry from [[ReActiveMicro]], and was officially released on February 15th, 2020. The 27-Series version of the project was officially released on April 1st, 2020.

RMHenry: Reverted edits by Mrtitanic777 (talk) to last revision by RMHenry

2022-06-21T05:29:09Z

Reverted edits by Mrtitanic777 (talk) to last revision by RMHenry

Mrtitanic777 at 05:05, 21 June 2022

2022-06-21T05:05:02Z

RMHenry: /* Issues, Fixes, And Repairs */

2022-03-02T20:51:04Z

Issues, Fixes, And Repairs

← Older revision		Revision as of 13:51, 2 March 2022
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	===Description of issue: The motherboard won't beep. Displays rolling blocks on the screen. Removal of F13 produces the issue.===~~<br />~~		===Description of issue: The motherboard won't beep. Displays rolling blocks on the screen. Removal of F13 produces the issue.===
	Location: F13, 74LS138, or sometimes a partly defective H10, or 8304.		Location: F13, 74LS138, or sometimes a partly defective H10, or 8304.
	[[Image:II_Screen-Issue1.jpg\|thumb\|left\|link=https://wiki.reactivemicro.com/images/1/12/II_Screen-Issue1.jpg]]		[[Image:II_Screen-Issue1.jpg\|thumb\|left\|link=https://wiki.reactivemicro.com/images/1/12/II_Screen-Issue1.jpg]]

RMHenry: /* Issues And Fixes */

2022-03-02T20:49:53Z

Issues And Fixes

← Older revision		Revision as of 13:49, 2 March 2022
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	</center>		</center>

	==Issues And ~~Fixes~~==		==Issues, Fixes, And Repairs==
	General guide to issue resolution.		General guide to issue resolution and how to fix common issues.

	Description of issue: The motherboard won't beep. Displays rolling blocks on the screen. Removal of F13 produces the issue.<br />
			===Description of issue: The motherboard won't beep. Stationary video image of rows or columns.===
			* Start with replacing the PSU with a known good unit. If it's an original PSU it's likely starting to have regulation issues and unable to fully power your motherboard. Fully rebuild or replace the PSU in this case and retest. ReActiveMicro sells the [https://www.reactivemicro.com/product/universal-psu-kit/ Universal PSU Kit] for those wanting to replace the guts of their original PSU. We also offer an [https://www.reactivemicro.com/product/service-power-supply-rebuild/ upgrade service] to install the Universal PSU Kit in case you want it done for you. Or we also sell the [https://www.reactivemicro.com/product/universal-enclosure-psu/ Universal Enclosure PSU] for those looking to retire their original PSU and keep it intact for their collection. You can also add meters and fans as an option.
			<br>

			* Next remove all but the first bank of RAM (closest to the keyboard end) and all ROMs but the F8 ROM (farthest left). If it boots then slowly add back the ROMs, then the DRAMs.

			If still no boot, then replace the bank 1 DRAMs one at a time with the pulled DRAMs from bank 2-3. If needed, repeat process with all DRAMs you have. [https://www.reactivemicro.com/product/16k-x-1bit-dram/ You can also obtain known good DRAMs from ReActiveMicro to help speed up this process.]
			<br>

			* Next reseat and/or clean the pins of all ICs. With 35+ year old ICs and sockets it's also likely something is tarnished and no longer making good contact. Apple also didn't use the best quality sockets. Some QD Electrical Cleaner may also be a good idea for suspected socket tarnish.

			If lucky one of the above processes will solve the issue. If unluckily, something like a dying/dead PSU or lack of line filter (Tripp Lite LC1800) or good and power strip (Panamax P360) could be the reason and possibly several ICs are now dead. For this kind of issue you can usually use a known good working board and swap ICs around to see if you can find the issue. [https://www.reactivemicro.com/.../apple-ii-plus-rev-7.../ Known good replacement boards can be purchased from ReActiveMicro]. Or just use the new board to retire the old one and enjoy another 30+ years of trouble free use rather than fixing issues like this a few times a year.



			===Description of issue: The motherboard won't beep. Displays rolling blocks on the screen. Removal of F13 produces the issue.===<br />
	Location: F13, 74LS138, or sometimes a partly defective H10, or 8304.		Location: F13, 74LS138, or sometimes a partly defective H10, or 8304.
	[[Image:II_Screen-Issue1.jpg\|thumb\|left\|link=https://wiki.reactivemicro.com/images/1/12/II_Screen-Issue1.jpg]]		[[Image:II_Screen-Issue1.jpg\|thumb\|left\|link=https://wiki.reactivemicro.com/images/1/12/II_Screen-Issue1.jpg]]

← Older revision		Revision as of 22:29, 20 June 2022
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	[[Image:IMG_20200206_085701304_HDR-Store-tiny.png\|thumb\|Apple II Plus ~~820-0044-D~~ RFI, Current Version\|link=https://wiki.reactivemicro.com/images/3/33/IMG_20200206_085701304_HDR1-Wiki-tiny.png]]		[[Image:IMG_20200206_085701304_HDR-Store-tiny.png\|thumb\|Apple II Plus Rev 7 RFI, Current Version\|link=https://wiki.reactivemicro.com/images/3/33/IMG_20200206_085701304_HDR1-Wiki-tiny.png]]

	The Apple II ''plus'' ~~820-0044-D~~ RFI project was started on April 20th, 2019 by Henry from [[ReActiveMicro]], and was officially released on February 15th, 2020. The 27-Series version of the project was officially released on April 1st, 2020.		The Apple II ''plus'' Rev 7 RFI project was started on April 20th, 2019 by Henry from [[ReActiveMicro]], and was officially released on February 15th, 2020. The 27-Series version of the project was officially released on April 1st, 2020.

	This marks the first full computer project released by ReActiveMicro. The concept is a replacement board which is known good and fully tested, to be used as a replacement for the original motherboard. This will allow the user a better experience and less issues moving forward. In contrast, most original motherboards now require constant maintenance in order to stay in a dependable running state. Compounding the situation, the original motherboard has low quality sockets, and old DRAMs and ICs which are power hungry and are well past their lifespan ratings.		This marks the first full computer project released by ReActiveMicro. The concept is a replacement board which is known good and fully tested, to be used as a replacement for the original motherboard. This will allow the user a better experience and less issues moving forward. In contrast, most original motherboards now require constant maintenance in order to stay in a dependable running state. Compounding the situation, the original motherboard has low quality sockets, and old DRAMs and ICs which are power hungry and are well past their lifespan ratings.
Line 17:		Line 17:

	==Kit Assembly==		==Kit Assembly==
	The Apple II ''plus'' ~~820-0044-D~~ RFI Kit is a total of 2160 pads or "''solder joints''" for the 93-Series kit, and 2174 pads for the 27-Series kit. It takes about 5 hours to fully assemble a kit if you have a decent iron, flux, and solder. The parts included with your kit and the PCB have basic labels. Those with intermediate knowledge should have little trouble assembling the kit from the labels on the parts, the bag, and the PCB. The images below of the motherboards can also be used for reference or to determine orientation, such as the diodes.		The Apple II ''plus'' Rev 7 RFI Kit is a total of 2160 pads or "''solder joints''" for the 93-Series kit, and 2174 pads for the 27-Series kit. It takes about 5 hours to fully assemble a kit if you have a decent iron, flux, and solder. The parts included with your kit and the PCB have basic labels. Those with intermediate knowledge should have little trouble assembling the kit from the labels on the parts, the bag, and the PCB. The images below of the motherboards can also be used for reference or to determine orientation, such as the diodes.


Line 188:		Line 188:

	==Project Differences: 93-Series/27-Series==		==Project Differences: 93-Series/27-Series==
	The Apple II ''plus'' ~~820-0044-D~~ RFI project from ReActiveMicro comes is two different variations, the 93-Series and the 27-Series boards.		The Apple II ''plus'' Rev 7 RFI project from ReActiveMicro comes is two different variations, the 93-Series and the 27-Series boards.

	Both motherboards operate exactly the same in all aspects, and are an exact clone of the original from Apple. The only difference is which family of system ROMs are natively supported on the board. The two options are the original 93-Series, and the later and more common 27-Series.		Both motherboards operate exactly the same in all aspects, and are an exact clone of the original from Apple. The only difference is which family of system ROMs are natively supported on the board. The two options are the original 93-Series, and the later and more common 27-Series.
Line 219:		Line 219:
	The TheROMExchange did a write up on this mod as well here: [https://theromexchange.com/blog/2nd-march-2021 https://theromexchange.com/blog/2nd-march-2021]		The TheROMExchange did a write up on this mod as well here: [https://theromexchange.com/blog/2nd-march-2021 https://theromexchange.com/blog/2nd-march-2021]

	==Differences: Apple II Revision 0 and Apple II ''plus'' ~~820-0044-D~~ RFI==		==Differences: Apple II Revision 0 and Apple II ''plus'' Rev 7 RFI==
	There are several key differences between the Apple II Revision 0 and Apple II ''plus'' ~~820-0044-D~~ RFI. Basically they are the same board, however the ~~820-0044-D~~ RFI has some key enhancements		There are several key differences between the Apple II Revision 0 and Apple II ''plus'' Rev 7 RFI. Basically they are the same board, however the Rev 7 RFI has some key enhancements

	*Power On Reset: The Rev 0 has no power on reset - the user must do it manually or have a Disk II Controller installed. The ~~820-0044-D~~ auto-resets itself on power up.		*Power On Reset: The Rev 0 has no power on reset - the user must do it manually or have a Disk II Controller installed. The Rev 7 auto-resets itself on power up.
	*ROMs: The Rev 0 came standard with Integer BASIC. The ~~820-0044-D~~ comes standard with Applesoft BASIC.		*ROMs: The Rev 0 came standard with Integer BASIC. The Rev 7 comes standard with Applesoft BASIC.
	*RAM: The Rev 0 can use 4k and 16k DRAMs. The ~~820-0044-D~~ is 'hard set' to only use 16k DRAMs.		*RAM: The Rev 0 can use 4k and 16k DRAMs. The Rev 7 is 'hard set' to only use 16k DRAMs.
	*Character Generator: The Rev 0 uses a 2513 ROM which is 5-bits. The ~~820-0044-D~~ uses a more common 27-series EPROM which is a full 8-bits.		*Character Generator: The Rev 0 uses a 2513 ROM which is 5-bits. The Rev 7 uses a more common 27-series EPROM which is a full 8-bits.
	*Video: The Rev 0 has several video issues which make them hard to use and limited 4 color palette for low and high-res. The ~~820-0044-D~~ fixed the video issues and expanded to color palette to 16 color low-res, and 6 color high-res.		*Video: The Rev 0 has several video issues which make them hard to use and limited 4 color palette for low and high-res. The Rev 7 fixed the video issues and expanded to color palette to 16 color low-res, and 6 color high-res.
	*Timing: There were several timing issues that were fixed in the ~~820-0044-D~~ design.		*Timing: There were several timing issues that were fixed in the Rev 7 design.
	*Power: The ~~820-0044-D~~ was enhanced with better power filtering to help prevent intermittent lockup issues reported in the Rev 0 design.		*Power: The Rev 7 was enhanced with better power filtering to help prevent intermittent lockup issues reported in the Rev 0 design.


	==Notices==		==Notices==
	;Character Generator / Video ROM (location A5)		;Character Generator / Video ROM (location A5)
	:The ROM on the ~~820-0044-D~~ RFI board is pinned for a 2716 EPROM. A 2732 also works as however the A11 address line is held 'high' on the motherboard, so only the 'top' half of the ROM is used. When programming a 2732 the firmware is loaded in to address 0800-0FFF.		:The ROM on the Rev 7 RFI board is pinned for a 2716 EPROM. A 2732 also works as however the A11 address line is held 'high' on the motherboard, so only the 'top' half of the ROM is used. When programming a 2732 the firmware is loaded in to address 0800-0FFF.

	:Also note worthy is the speed of the ROM used. Some ROMs with an access time of 350nS tend to cause artifacts on the screen when used. 300nS or better should be used. It has been getting harder to find 250-300nS speed grades for 2716 EPROMs, so 2732 ROMs are used to address this issue.		:Also note worthy is the speed of the ROM used. Some ROMs with an access time of 350nS tend to cause artifacts on the screen when used. 300nS or better should be used. It has been getting harder to find 250-300nS speed grades for 2716 EPROMs, so 2732 ROMs are used to address this issue.

← Older revision		Revision as of 22:05, 20 June 2022
Line 2:		Line 2:


	[[Image:IMG_20200206_085701304_HDR-Store-tiny.png\|thumb\|Apple II Plus ~~Rev 7~~ RFI, Current Version\|link=https://wiki.reactivemicro.com/images/3/33/IMG_20200206_085701304_HDR1-Wiki-tiny.png]]		[[Image:IMG_20200206_085701304_HDR-Store-tiny.png\|thumb\|Apple II Plus 820-0044-D RFI, Current Version\|link=https://wiki.reactivemicro.com/images/3/33/IMG_20200206_085701304_HDR1-Wiki-tiny.png]]

	The Apple II ''plus'' ~~Rev 7~~ RFI project was started on April 20th, 2019 by Henry from [[ReActiveMicro]], and was officially released on February 15th, 2020. The 27-Series version of the project was officially released on April 1st, 2020.		The Apple II ''plus'' 820-0044-D RFI project was started on April 20th, 2019 by Henry from [[ReActiveMicro]], and was officially released on February 15th, 2020. The 27-Series version of the project was officially released on April 1st, 2020.

	This marks the first full computer project released by ReActiveMicro. The concept is a replacement board which is known good and fully tested, to be used as a replacement for the original motherboard. This will allow the user a better experience and less issues moving forward. In contrast, most original motherboards now require constant maintenance in order to stay in a dependable running state. Compounding the situation, the original motherboard has low quality sockets, and old DRAMs and ICs which are power hungry and are well past their lifespan ratings.		This marks the first full computer project released by ReActiveMicro. The concept is a replacement board which is known good and fully tested, to be used as a replacement for the original motherboard. This will allow the user a better experience and less issues moving forward. In contrast, most original motherboards now require constant maintenance in order to stay in a dependable running state. Compounding the situation, the original motherboard has low quality sockets, and old DRAMs and ICs which are power hungry and are well past their lifespan ratings.
Line 17:		Line 17:

	==Kit Assembly==		==Kit Assembly==
	The Apple II ''plus'' ~~Rev 7~~ RFI Kit is a total of 2160 pads or "''solder joints''" for the 93-Series kit, and 2174 pads for the 27-Series kit. It takes about 5 hours to fully assemble a kit if you have a decent iron, flux, and solder. The parts included with your kit and the PCB have basic labels. Those with intermediate knowledge should have little trouble assembling the kit from the labels on the parts, the bag, and the PCB. The images below of the motherboards can also be used for reference or to determine orientation, such as the diodes.		The Apple II ''plus'' 820-0044-D RFI Kit is a total of 2160 pads or "''solder joints''" for the 93-Series kit, and 2174 pads for the 27-Series kit. It takes about 5 hours to fully assemble a kit if you have a decent iron, flux, and solder. The parts included with your kit and the PCB have basic labels. Those with intermediate knowledge should have little trouble assembling the kit from the labels on the parts, the bag, and the PCB. The images below of the motherboards can also be used for reference or to determine orientation, such as the diodes.


Line 188:		Line 188:

	==Project Differences: 93-Series/27-Series==		==Project Differences: 93-Series/27-Series==
	The Apple II ''plus'' ~~Rev 7~~ RFI project from ReActiveMicro comes is two different variations, the 93-Series and the 27-Series boards.		The Apple II ''plus'' 820-0044-D RFI project from ReActiveMicro comes is two different variations, the 93-Series and the 27-Series boards.

	Both motherboards operate exactly the same in all aspects, and are an exact clone of the original from Apple. The only difference is which family of system ROMs are natively supported on the board. The two options are the original 93-Series, and the later and more common 27-Series.		Both motherboards operate exactly the same in all aspects, and are an exact clone of the original from Apple. The only difference is which family of system ROMs are natively supported on the board. The two options are the original 93-Series, and the later and more common 27-Series.
Line 219:		Line 219:
	The TheROMExchange did a write up on this mod as well here: [https://theromexchange.com/blog/2nd-march-2021 https://theromexchange.com/blog/2nd-march-2021]		The TheROMExchange did a write up on this mod as well here: [https://theromexchange.com/blog/2nd-march-2021 https://theromexchange.com/blog/2nd-march-2021]

	==Differences: Apple II Revision 0 and Apple II ''plus'' ~~Rev 7~~ RFI==		==Differences: Apple II Revision 0 and Apple II ''plus'' 820-0044-D RFI==
	There are several key differences between the Apple II Revision 0 and Apple II ''plus'' ~~Rev 7~~ RFI. Basically they are the same board, however the ~~Rev 7~~ RFI has some key enhancements		There are several key differences between the Apple II Revision 0 and Apple II ''plus'' 820-0044-D RFI. Basically they are the same board, however the 820-0044-D RFI has some key enhancements

	*Power On Reset: The Rev 0 has no power on reset - the user must do it manually or have a Disk II Controller installed. The ~~Rev 7~~ auto-resets itself on power up.		*Power On Reset: The Rev 0 has no power on reset - the user must do it manually or have a Disk II Controller installed. The 820-0044-D auto-resets itself on power up.
	*ROMs: The Rev 0 came standard with Integer BASIC. The ~~Rev 7~~ comes standard with Applesoft BASIC.		*ROMs: The Rev 0 came standard with Integer BASIC. The 820-0044-D comes standard with Applesoft BASIC.
	*RAM: The Rev 0 can use 4k and 16k DRAMs. The ~~Rev 7~~ is 'hard set' to only use 16k DRAMs.		*RAM: The Rev 0 can use 4k and 16k DRAMs. The 820-0044-D is 'hard set' to only use 16k DRAMs.
	*Character Generator: The Rev 0 uses a 2513 ROM which is 5-bits. The ~~Rev 7~~ uses a more common 27-series EPROM which is a full 8-bits.		*Character Generator: The Rev 0 uses a 2513 ROM which is 5-bits. The 820-0044-D uses a more common 27-series EPROM which is a full 8-bits.
	*Video: The Rev 0 has several video issues which make them hard to use and limited 4 color palette for low and high-res. The ~~Rev 7~~ fixed the video issues and expanded to color palette to 16 color low-res, and 6 color high-res.		*Video: The Rev 0 has several video issues which make them hard to use and limited 4 color palette for low and high-res. The 820-0044-D fixed the video issues and expanded to color palette to 16 color low-res, and 6 color high-res.
	*Timing: There were several timing issues that were fixed in the ~~Rev 7~~ design.		*Timing: There were several timing issues that were fixed in the 820-0044-D design.
	*Power: The ~~Rev 7~~ was enhanced with better power filtering to help prevent intermittent lockup issues reported in the Rev 0 design.		*Power: The 820-0044-D was enhanced with better power filtering to help prevent intermittent lockup issues reported in the Rev 0 design.


	==Notices==		==Notices==
	;Character Generator / Video ROM (location A5)		;Character Generator / Video ROM (location A5)
	:The ROM on the ~~Rev 7~~ RFI board is pinned for a 2716 EPROM. A 2732 also works as however the A11 address line is held 'high' on the motherboard, so only the 'top' half of the ROM is used. When programming a 2732 the firmware is loaded in to address 0800-0FFF.		:The ROM on the 820-0044-D RFI board is pinned for a 2716 EPROM. A 2732 also works as however the A11 address line is held 'high' on the motherboard, so only the 'top' half of the ROM is used. When programming a 2732 the firmware is loaded in to address 0800-0FFF.

	:Also note worthy is the speed of the ROM used. Some ROMs with an access time of 350nS tend to cause artifacts on the screen when used. 300nS or better should be used. It has been getting harder to find 250-300nS speed grades for 2716 EPROMs, so 2732 ROMs are used to address this issue.		:Also note worthy is the speed of the ROM used. Some ROMs with an access time of 350nS tend to cause artifacts on the screen when used. 300nS or better should be used. It has been getting harder to find 250-300nS speed grades for 2716 EPROMs, so 2732 ROMs are used to address this issue.