A3000 Logic Chips: U202, U203, U701, U714

[metalman]

 Noticed this ebay listing

A3000 Logic Chips U202, U203, U701, U714

Anyone know what problems or symptoms are associated with failure of the original chips that replacing them with these new chips would repair?

[adolescent]

The U202/U203 fixes the screen-speckle problem.  (As you move the mouse, etc. small speckles a few pixels wide appear randomly on the screen.  Sometime worse when there is high I/O.)  I had mine replaced from AmiTrix in 94 or 95.  

[dannyp1]

The new ones also run much cooler.  If you are serious about your A3000 you want to get a set of these.

Dan

[Castellen]

I've written some additional information on these programmable logic devices here.  I can also supply a set of 4 programmed Lattice devices for US$21 *including* worldwide freight.

[Tron2k2]

Are these chips used in the GBA 1000?  Would I need them for it?

[Castellen]

No, only applies to the A3000 & A3000T.  They used the older style PAL devices and are prone to heat problems due to poor air circulation in the case.

[metalman]

Castellen wrote:
I've written some additional information on these programmable logic devices here.  I can also supply a set of 4 programmed Lattice devices for US$21 *including* worldwide freight.

Video speckles & random disk errors!

I've observed both problems, so I NEED replacemets!

Questions:

Are there any practical differences between the Atmel GAL chips vs Lattice GAL chips on power consumption, speed, ect.

Would substituting faster than 25ns chips as replacement chips have any advantages.

[Castellen]

If these devices are the cause of your problems, you're likely to notice video problems after the computer has been running for a short time.  It'll probably be cool when you first power it on, so usually you won't see problems until it's started heating up.

The Atmel and Lattice devices do exactly the same job, you won't notice any difference between them in this application.

Same goes for the speed, even the slowest GAL devices are fast enough for operation in the A3000.  There's no advantage in paying extra for the faster rated parts.

[Retro_71]

Castellen wrote:
If these devices are the cause of your problems, you're likely to notice video problems after the computer has been running for a short time.  It'll probably be cool when you first power it on, so usually you won't see problems until it's started heating up.

The Atmel and Lattice devices do exactly the same job, you won't notice any difference between them in this application.

Same goes for the speed, even the slowest GAL devices are fast enough for operation in the A3000.  There's no advantage in paying extra for the faster rated parts.

I have to say that i have bought these from Castellen and am very happy with them. You can't go wrong with the stuff he has.

[metalman]

Castellen wrote:
If these devices are the cause of your problems, you're likely to notice video problems after the computer has been running for a short time.  It'll probably be cool when you first power it on, so usually you won't see problems until it's started heating up.

The video sparkles and the harddrive read problems show up after the computor is on for a while, elapsed time until random problems develope seems to be getting shorter.

Castellen wrote:
Same goes for the speed, even the slowest GAL devices are fast enough for operation in the A3000.  There's no advantage in paying extra for the faster rated parts.

The cost difference is very minimal for 25ns vs 15ns chips. I'm asking if there might be some theoretical advantage, however slight.


Do you have a Paypall account?

[Castellen]

Sounds like that's your problem then.

There is no advantage with using the faster parts.  Internally they probably use the same die.  During manufacture the maximum speed is tested, ones which perform correctly at higher speeds are sold at a premium price.  Ones which fail at higher speeds are de-rated and tested accordingly then sold at lower prices.

I do have a PayPal account, same as my Email address.  See here for contact details.  Price will be US$22 to cover the PayPal 5%.

Hope that helps.