Source for inexpensive 6821 pulls

Also I'm not sure the above is as effective as you think. One of the many issues with Chinese stuff is just the total variability. Even if you go with a "reliable" Chinese seller such as UTsource they're not stocking anything, they're sourcing from the open market. One order could be ok, the next not.

Yes, I know. I've been told by them directly that they are at the mercy of their "suppliers". Grrr.
Still, ... it betters the odds, IMHO.

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I just bought a bunch of used 6809Es from UTsource. They're scheduled to arrive today. If they're not total crap maybe I will take another dip with the 6821s. :)

Two different date codes on the (15) 6809Es. 1437 and 1108; both clearly bullshit. 4 of the 1437s fail on the NOP tester (one is visibly melted). Of the 1437s that seem to work there are at least two different packaging/ejection molding styles.

I'll test the working ones more fully on an actual Williams game and file a dispute for the bad ones. Still at least I didn't get relabeled 6809s like this guy. I can't imagine trying to explain "it's bad" to a Chinese seller when the test shows it passes :D
 
Many years ago I purchased some 6809 / E from Jameco as I was repairing a bunch of WMS boards.
All the "pulls" were BAD. Since then I've never purchased a thing from Jameco. Grrrr. YMMV - as some still swear by them. But not me.
 
OK, I just purchased the cheapest 6821 you can find for $1.12US each. I bought 10 with free shipping.
Will report back if they pass the NeoLoch test. :)

View attachment 788233

@dorkshoei

OK, a month later (thanks Canada Post) I received my TEN samples of cheapo $1.12 6821.
Testing in the Neoloch Inquisitor, I found than 9/10 PASS and 1/10 FAIL.
The FAILED unit passed all tests with the exception of E24/E25/E26 which relates to the CB2 Strobe function.

So, what can we conclude?
Well, maybe I just got lucky. :)

All the ICs had the same top MOTOROLA markings/text which is suspicious. The 40pin package had slight differences (pin 1 marking/hole/notch etc) on most of them. One of them had text on the underside noting it was really a 68C21.

If anyone else wants to roll the dice for some cheap MC6821P, here's the Ebay seller's info:

2pcs MC6821P MC6821 Peripheral Interface Adapters DIP-40 #K1995
$2.24US (for 2); free shipping
ebest-chips
(2890)
96.5% positive
eBay item number:373175270132


As always, YMMV. :)
 
All the ICs had the same top MOTOROLA markings/text which is suspicious. The 40pin package had slight differences (pin 1 marking/hole/notch etc) on most of them. One of them had text on the underside noting it was really a 68C21.

I think more than suspicious :D

I ended up getting money back from UTsource on the 6809Es as they were clearly remarked. Impossible date codes. Identical labeling/date/lot markings but at least 3 different ejection molding/packaging types.

If anyone else wants to roll the dice for some cheap MC6821P, here's the Ebay seller's info:

Without a method to test I'm not going there but I'm glad you emerged mostly unscathed :D

I'll keep looking for a cheaper source.
 
*6809 CPU Testing

You can test the 6809/6809e's on a Williams JROK board. (@jrok) designed the board to run on either processor and identifies which one it is on the screen during boot. I have bought a ton of 6809e's from eBay and the ones that don't work nearly always turn out to be a 6809.

I think the real issue is the guys 'Refurbishing' them in China think they are all the same (and obviously don't test).

~Brad
 
I was at my local electronics surplus store on Friday and found a quantity of 6821s for $3 each. NOS. Close enough to my target price of $2.50. Patience grasshopper :)
 
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