Re: 82S141 PROMs
I've encountered burned bi-polar PROMs sold as "new" only once, and the seller refunded my money, so it wasn't a big problem.
arcadechips.com has excellent prices for proms, including a good selection of bi-polar varieties.
--- In email@example.com, Mike Loewen <mloewen@...> wrote:
> On Fri, 27 Jan 2012, Mike Loewen wrote:
> > I'm looking for a source for at least six Signetics 82S141 Bi-polar
> > PROMs for my HP project. Common substitutes are National 74S474, MMI
> > 6341-1, TI 28S46, Harris 7641-5, AMD 27S31. Best price I've found so far
> > is $12 a piece at hobbyroms.com. I was faked out by a false lead at
> > electronicplus.com - they don't have any left.
> > Any ideas on sources? My Data I/O 29B should be able to handle them.
> I received six National 74S474 PROMs from Unicorn Electronics, and
> discovered that three of them were not blank (on my Data I/O 29B). Is
> this a common occurrence for old stock?
> Mike Loewen mloewen@...
> Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
- Hi Mike,
I think it is common. I think a lot of these parts were ordered pre-programmed at the factory, so a lot of "New" old-stock parts may actually be programmed, and it would be difficult for a distributor to tell without actually testing.
For what it's worth, I hadn't heard of Unicorn at that time, and by now, I have bought a number of parts from them, and have found their service and their parts to be excellent. I would definitely call them if your part it pre-programmed.
A while back, I repaired an Asteroids Deluxe board, and I bought several 74S287 and 82S129 proms from one mail order company and Fry's, and found them all to be pre-programmed. At first I thought I was doing something wrong. Here's the thread:
I finally got a couple of blank PROMS from a vintage arcade parts seller online.
BTW, here's my repair log for that board:
- On Tue, 14 Feb 2012, Mike wrote:
> I've encountered burned bi-polar PROMs sold as "new" only once, and the seller refunded my money, so it wasn't a big problem.Thanks, Mike, I found arcadechips.com last night and he supposedly has
> arcadechips.com has excellent prices for proms, including a good selection of bi-polar varieties.
> Mike Willegal
them in stock. I left a message, asking about them, as well as one for
Mike Loewen mloewen@...
Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/