C128 Guy
Experienced Member
2532's are still available used. If you have to order something why not order those instead of building an adapter for the incorrect chip? Unless you want switching.
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4k EPROM recommendation for PET 4032 option socket
- Thread starter RobbyD
- Start date
Radix
Experienced Member
Yes, I got a dozen or more, but they were twice as expensive than the adaptors with 27C512 EPROMs - and had a poor reliability, as well as increasingly hard to find at times, while the adaptor can use a wide variety of newer and cheaper parts that are easy to source... And the ability to run the real Commodore diagnostics is really useful too!
SiriusHardware
Veteran Member
Be aware that some of the popular modern cheapo USB powered programmers don't support older 25V / 21V EPROM devices as well as they should because they can't generate more than about 18V VPP maximum. In my opinion programmers which claim to support certain devices but actually don't are not fit for purpose. My small stock of 2532s are all Hitachi branded devices and came from an ebay seller in Goole, east Yorkshire (England). The programmer I use for them is an old Needhams EMP-20 (Complete with DOS support software and a suitably ancient machine to run it on).
Hugo Holden
Veteran Member
Here is the site (maybe you got another site because of the sh- prefix).
I have been buying from them for years. It is all their own old stock. They even once sorted though for me and found IC's with specific 70's date codes for some of my Pong replicas.
Start searching your favorite vintage IC's and transistors ! If you want they have the MC3446AP and MC3446N. This time another song applies:
If you want it, here it is, come and get it
Mmh, make your mind up fast
If you want it, any time, I can give it
But you'd better hurry 'cause it may not last.
In my experience, if a part starts to become rare, and people know it, the remaining stocks appear to evaporate exponentially more quickly toward the end because they are bought up for spare parts, not just repairs. One example of this effect was the classic Speech IC, the Votrax SC-01A. It got to the point where the last supplier who had them sold out all of his stock abruptly when the numbers got below about 40 pcs, then they evaporated suddenly, like ether, were all gone for good.
SH-Halbleiter Electronic Vertrieb GmbH
Vertrieb von Halbleitern und elektronischen Bauteilen.
www.sh-halbleiter.de
Hugo Holden
Veteran Member
I never buy used IC's if I can avoid it. Because you don't know what abuse they have been subject to in the past.
There are plenty of vintage new old stock TMS2532JL's available, I listed a link before to some on the bay. One other advantage is, you don't have to bother erasing them, as the new ones come as blanks.
They seem like good value for a quality unused part:
Tms2532jl-45 2532 Texas Instruments 32k EPROM - UV Eraseable for sale online | eBay
Find many great new & used options and get the best deals for Tms2532jl-45 2532 Texas Instruments 32k EPROM - UV Eraseable at the best online prices at eBay! Free shipping for many products!
www.ebay.com
There are a number of TMS2532JL's coming out of China, I think most are ok:
1x 2S32JL-45 2532JL-4S 2532JL45 2532JL 45 TMS 2532JL-45 TMS2532JL-45 CWDIP24 IC | eBay
Find many great new & used options and get the best deals for 1x 2S32JL-45 2532JL-4S 2532JL45 2532JL 45 TMS 2532JL-45 TMS2532JL-45 CWDIP24 IC at the best online prices at eBay! Free shipping for many products!
www.ebay.com
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C128 Guy
Experienced Member
Most of the "new" eproms on ebay are old ones with their pins pressed straight again and dipped into a solder pot to make the legs look new. I hate getting these used "refurb" eproms covered in solder. I'd rather buy a good used pull and erase it myself than try to shove an eprom into a socket with extra thick legs covered in solder. Even worse - they remark the eproms so you have no idea what they really are! I've had to guess before to get some to program since they were incorrectly labeled.
I have stacks of these "new" eproms I have claimed back to ebay sellers that are not new.
Hugo Holden
Veteran Member
Good Lord no, I very rarely fall for fakes or refurbished pulls.
One reason is I inspect the auction photos closely looking for indications of pulls or re-labelled parts. I look for age appropriate markings and the appearance of the pins. Mostly when I can I try to buy mil spec parts too.
Then, when the part arrives I subject it to examination under the binocular microscope.
Occasionally, and it happened recently, a seller sent me a fake re-labelled part. It was not obvious from the auction photo, but is was a rare part and no other options were available at the time, so I took the risk and got kicked in the chops.
After a while though, buying vintage IC's from many ebay vendors & others, I get to find out who has the original NOS parts, who is selling fakes and who are merely on-sellers and claim to have the part, when they don't, and only try to acquire it after a customer orders it.
There is a test you can do to determine if the seller is a genuine stocking supplier, or a re-seller. There was a memory IC where the manufacturers "planned" to make it. They released its data sheet, which circulated the internet. The IC was in fact never made and never shipped. The non stocking suppliers create their IC data lists from internet searches (that don't actually hold real stock) so if you are contemplating buying from an IC supplier and they have the IC part number CY9C6264 on their stock list, don't buy from them. The details are on page 20 of this article:
C128 Guy
Experienced Member
You don't always get what is pictured either !! That is usually what happens to me.
MicroCoreLabs
Experienced Member
- Joined
- Feb 12, 2016
- Messages
- 283
For debugging you could try my MCL65+ which is a 6502 drop-in emulator using a Teensy 4.1. You can emulate your ROMs rather than using the socketed ones. Takes a few seconds to try new ROMs this way...
RobbyD
Member
Just to close out on the original question for this thread: I sourced some TMS2532JL EPROMS, burned various 4K ROMS on them, placed them in socket UD12 on my PET 4032 and they all worked fine. Thanks everyone for all the tips and pointers.