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Model 4: Gate Array vs Non-Gate Array

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taos23

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I'm installing model 4 electronics in a nice Model 3 chassis. I know Radio Shack offered Model 3 upgrade kits back in the day (and those were probably non-gate array motherboards) however do collectors prefer Gate Array or Non-Gate Array electronics in terms of reliability? I'm guessing newer GA motherboards are considered newer/better/simpler, on the other hand there seem to be a lot more NGA motherboards on eBay for parts and replacement.
 
taos23 said:
I'm installing model 4 electronics in a nice Model 3 chassis. I know Radio Shack offered Model 3 upgrade kits back in the day (and those were probably non-gate array motherboards) however do collectors prefer Gate Array or Non-Gate Array electronics in terms of reliability? I'm guessing newer GA motherboards are considered newer/better/simpler, on the other hand there seem to be a lot more NGA motherboards on eBay for parts and replacement.
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As someone who has repaired quite a few of these, the GA are much easier to work on and fix if you have the parts. Having said that, the parts that fail are not easily found because they were proprietary for that board. The non gate arrays are very easy to find most parts for. But, on the Model 4 (4P is a different animal) you then had an off board RS232 and off board floppy controller. I've seen a few video support chips fail, a few RS232 parts fail, and those require another one to cannibalize. Tearing a perfectly good Model 4/4P apart is the only way to find these or from a partially broken one that had one of the other chips fail.

I've also seen more than my share of the CRTC chip fail on both GA/Non GA boards, more common than anything short of the line drivers for serial failing.

I have a GA in my restored 4, but I'd be just as happy with a non GA. Its the video board/CRT difference and key locations that really differentiate them, where the GA is much better. There were like 4-5 different video boards in the Model 4/4P, and the earliest ones were the same as the Model III. To me longevity would be putting a non GA board in the GA 4P or 4, but the 4 has that PAL for the 128 kit, which is really just nice to have for a RAM disk or a few apps.

Oh yeah, the non GA 4 ran a little slower due to wait states. not sure if there was ever a good way to solve that one.
 
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Model 3:4 NGA chassis.jpgModel 4 GA chassis.jpgYou will NOT be able to mount a Model 4GA or 4D motherboard into the Model 3 chassis ---- refer to the attached photos

I do have Model 4 bare chassis and case available if you are interested (send me a PM or preferably an email to JAYNEWIRTH@VERIZON.NET

Hope this helps
 
To repack a computer means, as I understand it, to put the boards, drives and other parts in a case other than the one it came in. For example, a model 4 in a 3 case. Steampunk is, among other things, an artistic style based on science fiction stories set in the 1800's, when all the technology would have been steam powered clockwork.

This is an example of a PC that has suffered a steampunk type modification:

2532442745_164ecbea7c.jpg

I was simply suggesting that instead of taking a jigsaw to a Model 3 case, why not have some real fun with the jigsaw, and build a Model 4 like Dr. Watson might have used?
 
Here's the hopped-up Model III NGA. After watching Ian's video about a Tandy 3 I wanted the prototype keyboard look :)

IMG_7553_800.jpg
 
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