Old HP ROM fixes/updates 3577A Network Analyzer - Page 1
Forum section: electronics / testgear

author: rx8pilot
author_rank: Super Contributor
timestamp: October 26, 2017, 01:07:24 am
content: I got an HP 3577A that will not boot up for what appears to be a ROM failure.The system begins the boot cycle and gets through the first self-test which is the panel LED's. The next self-test is the ROM which detects an error at block 3. I believe that is the beginning of the boot code. After that, it actually continues to check the RAM which passes. After a very brief message that the RAM has passed, the screen is blanked and it simply beeps for eternity.I checked the usual suspects - voltage rails, contacts, jumpers, etc. Nothing out of place. The front panel has some sticky buttons which may trigger the beeping. The keyboard self-test immediately follows the RAM test.Does anyone know if a faulty ROM is a repairable event for these old mid-80's instruments? Maybe load through the GPIB?

author: precaud
author_rank: Frequent Contributor
timestamp: October 26, 2017, 01:21:41 am
content: Quote from: rx8pilot on October 26, 2017, 01:07:24 amI can't answer your ROM question, but definitely make sure none of the keys are sticking in before powering it up. That causes bizarre bahavior in many HP instruments from that period (and prior).

author: TheSteve
author_rank: Unknown
timestamp: October 26, 2017, 01:23:11 am
content: The firmware is on KO4BB's site -http://www.ko4bb.com/getsimple/index.php?id=manualsSearch for the 3577A

author: rx8pilot
author_rank: Super Contributor
timestamp: October 26, 2017, 03:07:40 am
content: Quote from: precaud on October 26, 2017, 01:21:41 amDefinitely - still trying to figure out how to get to the keyboard/buttons. The old HP gear is quite a party to disassemble. Pretty sure the display soft keys are causing a problem since they don't really return after being pushed.Quote from: TheSteve on October 26, 2017, 01:23:11 amThis is stunning. Someone has the images and posted them. How cool is that?I need an EEPROM programmer now to try it out. Thank you for the link!

author: precaud
author_rank: Frequent Contributor
timestamp: October 26, 2017, 05:06:32 am
content: Quote from: rx8pilot on October 26, 2017, 03:07:40 amThe front panels are no fun. But once you have it out, it is all very repairable. It sounds like the little metal leaf springs are missing from some of the switches. You'll probably find a few of them scattered inside the unit when you pull the panel. Keep an eye out for 'em.QuoteJust put some tape on a set of pliers and pull them out. That will be good enough for testing purposes. I bet some of your errors will go away.

author: rx8pilot
author_rank: Super Contributor
timestamp: October 26, 2017, 04:30:42 pm
content: I think I am going to study the exploded view a little more....The goal is to get access to the display buttons without breaking 3 more things along the way - not sure yet how to get there without disturbing everything. The mechanical architecture of this particular unit is rather nice from what I have seen so far. Everything on a backplane with connections that are easy to get to. The power supply is fully accessible on the bottom, the CRT pots are actually brought out the back of the unit, test points are clearly marked. These things were a no expense spared project back in the day. Rather amazing.So, I am ordering a set of EPROMS today - there are 8 of them in the main processor. The originals are PROMs that I plan to add sockets and EPROMs. Can't say how happy I am to find that some amazing person took the time to pull the binary's off his 3577A and post them for other to repair with. This unit may have a dozen other issues but I can only find out if the digital section boots up. At this point, I am assuming that the super cheap TL866a programmers will do the trick. All these years of fiddling and I never owned an EEPROM programmer.The EEPROMs described in the notes are not available at DigiKey or Mouser, but Jameco has some. I will probably get a couple extra just in case too.The good news is that the CRT is still working and looks rather bright. This instrument will only be needed a handful of times each year, so I doubt I will have to worry much about an LCD conversion or CRT replacement.

author: rx8pilot
author_rank: Super Contributor
timestamp: October 26, 2017, 05:45:43 pm
content: The schematics out and about on the web seem to be scanned at about 30dpi and then through 10 passes of JPG compression.Looking for a functional schematic - not opposed to buying an HP original off of eBay if I cannot find it.

author: edavid
author_rank: Super Contributor
timestamp: October 26, 2017, 05:47:41 pm
content: Artek sells a good quality scan for $12.50http://artekmanuals.com/manuals/hp-manuals/

author: rx8pilot
author_rank: Super Contributor
timestamp: October 26, 2017, 06:13:39 pm
content: Quote from: edavid on October 26, 2017, 05:47:41 pmBRILLIANT!!!!Ordered.....Can anyone tell the difference in quality? Artek even labeled all the chapters to make searching way easier. Fantastic.

author: precaud
author_rank: Frequent Contributor
timestamp: October 26, 2017, 10:39:34 pm
content: Quote from: rx8pilot on October 26, 2017, 04:30:42 pmYes, very well-executed. My only beef with mine is, I wish it had more RBW's available, like a 1-3-10... sequence.

author: rx8pilot
author_rank: Super Contributor
timestamp: November 02, 2017, 05:29:34 am
content: IT'S ALIIIIIIIVE!!!Details to follow.....but this beast is working. Pretty excited about it. I have not yet done any real tests with it, but it passes all the self-tests and responds as expected.

author: precaud
author_rank: Frequent Contributor
timestamp: November 02, 2017, 11:36:10 am
content: Looks great!

author: rx8pilot
author_rank: Super Contributor
timestamp: November 02, 2017, 05:51:16 pm
content: So far, the system seems to be working (although 15 years out of calibration). The CRT is in fantastic shape, the source port is good, the inputs are good, all the buttons are working, etc....The initial failure mode was that after it was powered on, it would just beep. Nothing on the display. I took the covers off to look for obvious things but found nothing. The inside was rather clean - even the fan was barely dusty. The service manual outlines the boot sequence but says nothing about a constant beeping. Considering it would not boot up - my first look was at the CPU card. While it was beeping at me, I noticed a reset button that re-boots the digital section of the system. When I pressed it, the result was the same as doing a power cycle but with one difference - the CRT was warmed up. When I reset the digital section with the CRT warm, I could see the error message pop up for about 1/2 a second before the screen blanked and the beeping started. This error message (in the pics above) clearly pointed to a specific ROM chip on a specific board. At this point, I thought the repair was over. When @TheSteve posted the link to the site where the ROM images were posted, it started looking much better.I ordered a TL866A programmer and a dozen EEPROMs to replace the (28pin DIP 256k PROM's. They arrived yesterday and I was successful in getting the EEPROMs programmed and proceeded to remove the originals off the board. I do not have a good through-hole de-soldering solution that can deal with these chips so I had to fake it. The original plan was to simply cut the legs and trash the chips, but that idea was abandoned because I wanted to be able to easily read the chips and compare them to the new ones. I only have a Sold-a-pult for de-soldering which does not work very well so I used my messy air-blast technique. Essentially - I melt the joint and use a fine tip compressed air gun to blow the solder out. It used Kapton tape to contain the splatter and it totally frees the chips with no whiskers that can pull pads off the board. You can see in the pics that it is a bit of a mess but zero damage to the board. Easy to clean with IPA. 224 pads - no problem.After the PCB was cleaned up, I installed sockets for the new EEPROMs and plugged them all in. The system booted up, passed all the checks and it looks like we are in business.Thanks @TheSteve for the tip - that was critical.The instrument will be helpful in testing control loop response at low frequencies.

author: Cubdriver
author_rank: Unknown
timestamp: November 02, 2017, 11:00:09 pm
content: Bravo! Nicely done. I'm happy to hear that you've revived the old beast!-Pat

author: sixtimesseven
author_rank: Frequent Contributor
timestamp: March 30, 2019, 12:20:21 am
content: Unfortunatly the ko4bb.com website seems to have vanishedDoes anyone still have the ROM images saved somewhere and would share them?Thank you in advance!

author: tautech
author_rank: Super Contributor
timestamp: March 30, 2019, 01:39:41 am
content: Quote from: sixtimesseven on March 30, 2019, 12:20:21 amStill there and still works:http://www.ko4bb.com/getsimple/index.php?id=manualsLinks to all of the good repositories are here:https://www.eevblog.com/forum/repair/repair-documents-and-links-sticky-me-please-mods/If you know of any other please post about them there.

author: 0culus
author_rank: Super Contributor
timestamp: March 30, 2019, 01:45:14 am
content: Nice! I've found that the first troubleshooting step for any piece of HP gear is to first check for mechanical issues. Stuck buttons, re-seat boards, clean contacts, etc. A lot of times that's the only thing actually wrong...they built stuff to last.

author: rx8pilot
author_rank: Super Contributor
timestamp: March 30, 2019, 02:06:26 am
content: I have these ROMs saved if they ever dissappear. This piece of gear is really worth keeping alive.Typet purly on my fone.

author: KE5FX
author_rank: Super Contributor
timestamp: March 30, 2019, 08:01:36 am
content: Quote from: sixtimesseven on March 30, 2019, 12:20:21 amDidier's ISP had a temporary DNS glitch, it should be back up soon.

author: JuanjoB
author_rank: Newbie
timestamp: May 25, 2025, 08:17:08 am
content: Hello,I am looking for the ROM image files. I tried to download them from KO4BB website but it didn't work. Can anybody please send them?Thanks in advanceJuanjo