Seeking an index of HP propriety part numbers, to real part numbers - Page 1
Forum section: electronics / testgear

author: TerraHertz
author_rank: Super Contributor
timestamp: December 16, 2013, 07:46:20 am
content: A HP 54121T scope I have uses an EPROM as a character generator. The instrument is open atm for another problem, but it's high time I backed this up, since it seems _other_ EPROMs in the thing need a refresh. Never did read this one when I archived the others, since it's soldered in.Only, I Just realized this one has only a HP part number. "1818-3319 837Z7SJ"It's an AMD device, but which one, what speed, etc?Has anyone seen a database of HP part numbers, with equivalent PNs?

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: December 16, 2013, 08:27:33 am
content: Mr. google finds this:http://home.cogeco.ca/~jbarnes20/hp_ref.htmcan't find your part in it, are you sure it is the correct transcribed number? Specs for jedec/ parallel bus devices usually can be guessed at by the speed of the cpu driving the bus. Hope it helps.Edit: sorry just expanded your picture and can read the number my self. One other option, you are going to desolder anyway, wouldn't the eprom programmer be able to read the device ID?

author: TerraHertz
author_rank: Super Contributor
timestamp: December 16, 2013, 11:28:45 am
content: Quote from: chickenHeadKnob on December 16, 2013, 08:27:33 amThere's no bus in this case, it's being used for character dot pattern generation. Yes, failing a nice easy table look-up, it will come down to scoping the pins to see what it's doing.QuoteErr... I might be wrong, but I'm pretty sure most of the EPROMs made in the 80s didn't have any device ID system. And my chip programmer manual agrees.Anyway, it's not important. The *other* problem with this HP 54121T is turning out to not be the simple 'faded code EPROM' I thought it would be. Verified all EPROMs, fault still present. Swaped CPU card (with EPROMs) with a known good one - fault still present. System has a 68000 controller, and is getting a bus fault/address error.Don't you hate that 'it was working last time I used it' thing?And a big raspberry to the HP of 1987, for producing a '54120T Service Manual' that contains no schematics. Not even for the power supply.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: December 16, 2013, 11:46:34 am
content: Well you certainly are (a) mutton for glunishment. Just the fondness for old logic analyzers puts you in hurt territory, as they age and become obsolescent faster than a crack whore and are less fun even when new. I am of that era and I hold no nostalgia for that age/class of instrument. Tek 22 series scopes on the other hand pull at my heartstrings, even though I don't haz my own one yet. My practical side always tell me to save the money towards another new DSO, which are continually becoming a better value proposition.

author: Unknown
author_rank: Unknown
timestamp: December 16, 2013, 12:14:03 pm
content: Agilent'sfind-a-partwill sometimes give useful information about HP p/ns. For example instruments it's used in and replacements.

author: PA0PBZ
author_rank: Super Contributor
timestamp: December 16, 2013, 01:13:40 pm
content: Hmm... first link in Google (well ok, first returned was the calculator) for 1818-3319 says:"AMD 1818-3319(Refurbish) (=D27C256-200V10) EPROM 256K 32Kx8 IC CER.DIP Package"(http://www.wellgainelectronics.com/amd1818-3319refurbish.aspx)

author: TerraHertz
author_rank: Super Contributor
timestamp: December 16, 2013, 01:24:17 pm
content: Yay! Found athttp://www.ko4bb.com/Manuals/HP_Agilent/HP_Cross-Reference.pdfIt's a garden variety 27C256, 200nSThe HP 54121T isn't a logic analyzer, it's a 20GHz digitizing 4-channel scope, also with high-res precision TDR, that is fantastic for doing PCB trace impedance verification.2nd pic is two together. Still trying to find why the left hand one gets intermittent bus fault errors.The sampling heads are separate, not visible in the pic.Though it's funny you should mention antique logic analyzers. Since as some people collect old scopes or multimeters, with me it's old logic analyzers.Edit: PA0PBZ, thanks, you beat me to it. I suppose I didn't find that because of not thinking to include 'AMD'.Anyway, I guess I should have mentioned that I really was after a more comprehensive HP part number cross reference, since I hit this problem all the time. I had a couple of old x-ref files, but they were really old and mostly useless.The ko4bb one seems to include up through the late 1980s.Oh, and it's OCR'd, so can be searched.

author: SeanB
author_rank: Super Contributor
timestamp: December 16, 2013, 02:54:26 pm
content: Odd bus errors, are the bus buffers in sockets? Often I found old buffers could go weak, or intermittent or have cracked solder joints, along with the old favourite of failing HP capacitors.

author: TerraHertz
author_rank: Super Contributor
timestamp: December 17, 2013, 01:30:20 am
content: By board swapping, the fault is definitely located on one board, called 'I/O A1'. See pic. The fault follows that board into a working system. (Hooray for actually having a 2nd working system.)That board happens to have a block of 16 x NEC D41464 64k x 4bit DRAMs.The fault isn't 'wiggle sensitive', but seems to occur in a narrow temperature range.Went over the board joint by joint with a microscope - no bad joints. Only two socketed chips, unrelated, and already reseated. The 3V lithium for parameters CMOS RAM is 3.1V.And sometimes the power-up RAM test fails. So I'm pretty confident it's an intermittently bad DRAM chip.Ha ha.. but which one? The built-in tests don't seem to have the facility to report specifics of which address/bits failed. Well done HP, not. Nor is there a schematic & parts layout. So it has to be direct localization, but...Don't have a card extender, and can't easily get at the chips in operation to try thermal methods. Might be possible with some improvisation.More raspberries to HP. This instrument's so-called 'service manual' is really intended to make people return the thing to HP for service. That may have flown back in the 1980s when when this thing was a top of the line, export restricted, secret-stuff marvel. Today it's nothing but really annoying.Edit to add: It appears to be a 6-layer board, with a lot of tracks between the internal power and ground planes.Top connectors: at left is the front panel interface, at right is the HP-IB.

author: marshallh
author_rank: Unknown
timestamp: December 17, 2013, 01:35:43 am
content: Sometimes original part no.s may be marked on the underside of the chip. Depends on the mfg

author: MrAureliusR
author_rank: Unknown
timestamp: December 21, 2013, 08:31:44 pm
content: Would the HP Analyzer thing that free_electron mentioned on the Amp Hour help you out? The 4004 I believe it was? Apparently invaluable in fixing old HP equipment. With the manual, it walks you through troubleshooting and can point you to the exact part (in some cases) that is failing.

author: TerraHertz
author_rank: Super Contributor
timestamp: December 22, 2013, 02:42:57 pm
content: Quote from: MrAureliusR on December 21, 2013, 08:31:44 pmYou're talking about Signature Analysis?That only works if the manual actually contains signature analysis data. The so-called 'service manual' for the HP 54121T doesn't have any such information.If only it did. I recently bought a Sony-Tektronix 308 Data Analyzer, which does signature analysis.