53132A bad display - Page 1
Forum section: electronics / testgear

author: Robaroni
author_rank: Frequent Contributor
timestamp: May 18, 2016, 11:58:55 pm
content: Does anyone have the display part number for the 53132A counter? I don't want the complete board, just the display itself. The complete board goes for around $550.00 US. I think it should be available as I changed the display on a 34401A I bought off ebay but that was a number of years ago.I'm glad these new instruments are going to OLED.Thanks for your time and help.Rob

author: uncle_bob
author_rank: Unknown
timestamp: May 19, 2016, 01:05:28 am
content: Quote from: Robaroni on May 18, 2016, 11:58:55 pmHiThe only source for the full custom display on the 53132A is the HP display board. I believe the 53131 board is the same part. You can occasionally find people who have stripped the display from the board. Either way, they aren't cheap and you likely are buying a used item.Bob

author: bitseeker
author_rank: Super Contributor
timestamp: May 19, 2016, 05:14:43 am
content: The display board part number is 53131-60002.US$1047 from Keysight.Unlike the 34401A, for which China is making VFDs, as far as I know no other HP instruments with VFD have alternative sources for new displays. You'll have to wait for someone to part out the display board from a device that died, or buy a parts unit.Quote from: Robaroni on May 18, 2016, 11:58:55 pmWhy are you glad about that? OLEDs burn out too. So, from that perspective they're not any better than VFD. For longevity, it's better to use LED or LCD.

author: 2x2l
author_rank: Contributor
timestamp: May 19, 2016, 05:46:57 am
content: Quote from: bitseeker on May 19, 2016, 05:14:43 am

author: bitseeker
author_rank: Super Contributor
timestamp: May 19, 2016, 05:58:55 am
content: China is just making the VFD (the glass part that contains the display). You'd have to desolder the old one and solder in the new one (carefully).

author: Robaroni
author_rank: Frequent Contributor
timestamp: May 19, 2016, 11:40:20 am
content: Were do you get the Chinese display? Ebay?Guys, let me ask you, as this is my first 53132A, does the fan run constantly when the instrument is plugged in, even if it's off?Thanks,Rob

author: TheSteve
author_rank: Unknown
timestamp: May 19, 2016, 11:57:36 am
content: Yes, the fan always runs.

author: Robaroni
author_rank: Frequent Contributor
timestamp: May 19, 2016, 12:34:28 pm
content: Thanks Steve!Now I just need a source for the Chinese display.Rob

author: bitseeker
author_rank: Super Contributor
timestamp: May 19, 2016, 05:32:00 pm
content: Yes, the Chinese displays are available on eBay. However, these are for the 34401A DMM. The annunciators will not be appropriate for other instruments; the numeric readout may not even work.http://www.ebay.com/sch/i.html?_kw=34401+(vfd%2Cdisplay)&_sacat=0

author: HighVoltage
author_rank: Super Contributor
timestamp: May 19, 2016, 09:30:15 pm
content: The Chinese 34401A display will definitively not work for the 53132A, they are very different, as bitseeker already pointed out.I think the only hope you can have is to find and other donor unit.

author: Robaroni
author_rank: Frequent Contributor
timestamp: May 20, 2016, 12:54:54 pm
content: OK, here's the story.I spoke to Keysight parts and found that you can not purchase individual parts for the 53131a/53132A. When I needed a new rotary encoder for my 33220A I bought it for under $3.00 US. I don't know if you can still do this with other instruments from them now, I bought the encoder when they were Agilent and I bought just the display for my 34401A when they were HP, it cost me $68!The display board for the 53131A/2A complete goes for over $1k US! Yikes! I did find some nice people in CA who had a board with display for $100 but the display is weak. So if you need the board itself and have a good display this might work for you. Do a Google search for TopTestDog with the part number 53131-60002, that's the board you want for both these counters and it works with the 181 too as far as I can tell.Ebay has a reputable seller with one good display left as of May 20, 2016 (I just bought one) for $250 plus $25 shipping.http://www.ebay.com/itm/271869857776?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AITThey sent me photos of the working board so I could see all the digits lit properly and the display looks strong.$250 might sound like a lot but I think my counter would be worthless without it as it's fading, so I bought it thinking that we may never see these displays kicking around when we really need them.Yes, I know the 34401A won't work in the 53132A, but thanks for your concern guys.Rob

author: bitseeker
author_rank: Super Contributor
timestamp: May 20, 2016, 05:26:47 pm
content: Glad you found one right away.We were concerned about the 34401A comment because the way it was worded sounded like you were going to attempt a non-compatible display swap. No worries.Note that the name is TopDogTest.

author: Robaroni
author_rank: Frequent Contributor
timestamp: May 21, 2016, 12:09:18 am
content: Thanks Bitseeker,I always appreciate to massive knowledge this site brings.Rob

author: bitseeker
author_rank: Super Contributor
timestamp: May 21, 2016, 04:15:03 am
content: Agreed. I look forward to hearing how your transplant goes.

author: HighVoltage
author_rank: Super Contributor
timestamp: May 21, 2016, 06:39:19 am
content: Show us some before and after pictures, if you can. It will be interesting to see how bright the new display really is.

author: Robaroni
author_rank: Frequent Contributor
timestamp: May 21, 2016, 12:53:08 pm
content: The other issue I have with counter is the fan constantly on. First, I'll have to see if there's dust build up on it but I'm wondering if the fan is primarily for the ovens which this counter doesn't have the option in. I don't like the oven in my instruments, they add heat and tax the internal power supply.I've mentioned this before around here, what I did was design a stand alone 10Mhz OCXO that I adjust to a rubidium standard which I'll be double checking against a GPSDO once it's built. I'm using two OCXO's, the Milliren 260 and Morion MV89A. Both are very good. In fact once I calibrate the OCXO to the rubidium I shut off the rubidium and only use it to check the OCXO every few months. These OCXO's hold frequency to a couple parts in 1x10-11 over a few month period.I attached a photo of the new meter with the OCXO as ref and the rubidium as input. I left it on for a few days and the drift was only a couple of parts in 1x10-12.Adjusting the OCXO is a breeze using the front knob that runs a quad encoder to a 12 digit DAC from a cheap Atmel uC. The internal voltage reference on the OCXO is pretty good but on my revision of the circuit I added an option to use an AD586 as the voltage ref.I'm waiting for the revised board to come back from my board house and then maybe I'll start a new thread with all the particulars. I really think this is a nice way to go. All you lose is the self calibrate on the 53131/2A but since the OCXO holds freq. so well it isn't a big deal.R

author: bitseeker
author_rank: Super Contributor
timestamp: May 21, 2016, 06:14:07 pm
content: Yes, the standby is to keep the reference stable and ready to go in an instant. Since you're going to have a common, external reference for your devices, you can at least turn down the fan speed.I'm not sure how much heat other components in there generate, so disabling the fan may or may not be safe. If you lab stays nice and cool and there's plenty of space around the instrument, it might be OK.

author: uncle_bob
author_rank: Unknown
timestamp: May 21, 2016, 09:06:19 pm
content: Quote from: bitseeker on May 21, 2016, 06:14:07 pmHiSlow down the fan and the power supply eventually self destructs. It also will do that if there simply is a bunch of dirt blocking the air flow a bit.Bob

author: TheSteve
author_rank: Unknown
timestamp: May 21, 2016, 09:31:58 pm
content: One option is to change the switch so it truly turns power on and off so there is no fan noise or power consumption when it is turned off. This mod is on my to-do list as I use a GPSDO for an external reference.Gerry has done a video on the mod - you can check it out here:

author: uncle_bob
author_rank: Unknown
timestamp: May 21, 2016, 09:35:35 pm
content: Quote from: TheSteve on May 21, 2016, 09:31:58 pmHiProbably best to add some sort of time delay in with the turn off. When the fan and the supply both go off at once ... temperature climbs. It doesn't kill the supply fast, but there is a noticeable impact if you look at a couple hundred counters over a decade or so.Bob

author: Robaroni
author_rank: Frequent Contributor
timestamp: May 21, 2016, 10:35:05 pm
content: It seems to me that the oven options might need the fan on continuously as the oven does draw anywhere up to 200 or 300ma but the simple crystal shouldn't draw more than a few ma. I don't have a schematic so I don't know if the crystal circuit is even powered in the standby position. It might be as the ovens must be power on continuously and it's probably much of the same hardwareMy 53132A sits right against the wall with the rear bumpers hitting it, in fact I use a right angle power cord as my bench depth is shallow. What I decided to do is measure the temperature right at the fan with the counter powered on doing measurements and off with just the fan on so I taped a temp prob sitting on the fan output.I'll do the test for a day and compare the temp to ambient. I'll report back.Has anyone felt around the power supply or checked its temp in standby? I did a prelim test taking readings and the instrument doesn't seem to get much above ambient at all. I'm wondering if HP just cut a corner to save a couple of bucks leaving it on with the crystal. It just doesn't make sense to me.Rob

author: bitseeker
author_rank: Super Contributor
timestamp: May 22, 2016, 12:06:38 am
content: Quote from: uncle_bob on May 21, 2016, 09:35:35 pmAh, good to know. Thanks, Bob.

author: TheSteve
author_rank: Unknown
timestamp: May 22, 2016, 01:43:38 am
content: I currently use a power bar to turn the power on/off to all of my equipment that keeps an OSC warm. I've noticed very little heat from my 53132A with a properly running fan that is clean. I'm not too worried about turning the power off to it where the fans stops right away.

author: uncle_bob
author_rank: Unknown
timestamp: May 22, 2016, 01:48:56 am
content: Quote from: TheSteve on May 22, 2016, 01:43:38 amHiWe didn't worry much about it either. Then we started loosing about 4 or 5 supplies a year ....Bob

author: Robaroni
author_rank: Frequent Contributor
timestamp: May 22, 2016, 12:14:00 pm
content: There has to be a reason. When I pull mine apart to change the display board I'll check the temps on the SMPS. If the fan is indeed cooling off the supply I should be able to see it.Could it be that your supplies are going for another reason, are you sure it is the fan being off? I've been monitoring the fan all night with the instrument on and then off. I'm just not seeing any great variation in the temp, maybe a degree or two but several variables could be causing it.I think Gerry's been running for awhile with his mod.Rob

author: uncle_bob
author_rank: Unknown
timestamp: May 22, 2016, 12:45:25 pm
content: Quote from: Robaroni on May 22, 2016, 12:14:00 pmHiOnce we started replacing fans, the supplies stopped dying.....Bob

author: Robaroni
author_rank: Frequent Contributor
timestamp: May 22, 2016, 01:23:39 pm
content: Replacing fans? Are you saying the fans went bad?R

author: uncle_bob
author_rank: Unknown
timestamp: May 22, 2016, 01:35:35 pm
content: Quote from: Robaroni on May 22, 2016, 01:23:39 pmHiNope, the dirt and the like got them really noisy. I suspect they were not moving as much air as they should have. We started pulling them wholesale and that did the trick.Bob

author: Robaroni
author_rank: Frequent Contributor
timestamp: May 22, 2016, 01:46:26 pm
content: Uncle Bob,Did these counters have any of the oven options?Rob

author: uncle_bob
author_rank: Unknown
timestamp: May 22, 2016, 01:53:48 pm
content: Quote from: Robaroni on May 22, 2016, 01:46:26 pmHiNope, we run them all of of external standards in multiple plants. They were purchased over at least a 10 year span, so no, we didn't get a uniquely bad batch. It took us a while to figure things out. A lot of 53181's bit the dust "donating" their power supply to the 131's and 132's. Yes, hanging on to the rest of the chassis (for the DISPLAY) would have been a really good idea.Bob

author: Robaroni
author_rank: Frequent Contributor
timestamp: May 22, 2016, 02:03:38 pm
content: Good to know, I'll make sure to check temps on the SMPS when I pull it apart to change the display.You should have kept the displays!We never throw anything out.... Sometimes this can work to our disadvantage!Rob

author: uncle_bob
author_rank: Unknown
timestamp: May 22, 2016, 03:39:36 pm
content: Quote from: Robaroni on May 22, 2016, 02:03:38 pmHiWe tend to do the same thing. When it gets to the point that you are renting space in multiple locations to keep "stuff" the finance boys start to get into the act. Eventually an edict comes down. Unfortunately I do the same thing here at home. The space runs $550 a month. That's about $100,000 over the last 15 years or so. Want to bet I could buy a lot brand new gear for $100K? Same logic applies at work except their rent was running about 10X mine.Bob

author: Robaroni
author_rank: Frequent Contributor
timestamp: May 22, 2016, 10:40:06 pm
content: Uncle Bob,Let me put this into perspective, my wife Nancy calls it the Robsonian!Rob

author: uncle_bob
author_rank: Unknown
timestamp: May 23, 2016, 12:03:01 am
content: Quote from: Robaroni on May 22, 2016, 10:40:06 pmHiMy wife is far less kind when referring to my collection of "fine stuff" ....Bob

author: bitseeker
author_rank: Super Contributor
timestamp: May 23, 2016, 01:45:54 am
content: I think if my stuff got a name it'd become part of the family. So, no naming here. However, the Robsonian sounds like a nice place to visit.

author: BarsMonster
author_rank: Contributor
timestamp: October 16, 2022, 11:35:45 pm
content: Many of remaining 5313* displays will die... I hope I will get one that will survive.To prolong it's lifetime - I am thinking about adding a switch to disable display when doing long measurements with logging. Did anyone ever did that and is there any hints?

author: artag
author_rank: Super Contributor
timestamp: October 17, 2022, 12:38:21 am
content: I have a number of instruments with VFDs. None of them seem to have degraded further while I've owned them, but some were quite faded when I acquired them. The oldest instruments are not necessarily those with the dimmest displays.My assumption is that, if powered up only when used, they will last a very long time but if powered on all the time because they're part of a production or test bench, they will fade in a few years. I doubt that dimming the display during a long measurement will help much unless you do that all day, every day.

author: Robaroni
author_rank: Frequent Contributor
timestamp: October 17, 2022, 12:43:52 am
content: Quote from: BarsMonster on October 16, 2022, 11:35:45 pmI remember that counter, I switched mine out for a Tektronix FCA3000. Doesn’t help you but from other Agilent/HP stuff I’ve had those displays last a pretty long time, My 34401A had a bad display and I changed it out, the new one lasted till I sold it. I replaced it with a NOS 34401A that does all the basic measurements on my bench now. You can leave it on doing testing but they go bad if you leave them on all day everyday for years. Usually when I have to leave a meter on for extended time I have the luxury of a Keysight 34465A which is a better measuring device.

author: pqass
author_rank: Super Contributor
timestamp: October 17, 2022, 02:16:11 am
content: Quote from: BarsMonster on October 16, 2022, 11:35:45 pmI suppose you can add a pair* of low value resistors (5R or so) in-line with each filament lead (with DPDT switch shorting the resistors for full brightness). That should dim the display down; prolonging the phosphor. I didn't see a "DISPLAY OFF" GPIB command like in the 34401A.* it needs to be a pair (for symmetry) since the filament is driven by 5.5VAC whose center-tap is 6.2V above ground (via VR2 zener).Service manual:http://www.ko4bb.com/getsimple/index.php?id=download&file=HP_Agilent/HP_53131A_53132A_53181A_Universal_Counter/HP_53131A_Universal_Counter_Service_Manual.pdfDC/DC+AC converter used (HP:0950-2325 = ERG:E2577VF):http://static6.arrow.com/aropdfconversion/21bc2cafea0620cdaf462a249c08dfffcf094564/e2577vf.pdfFYI: HP manual pinout seems to be off by one.ALTERNATIVELY, if possible,you can break the connection between U2 (SN75518FN) pin 21 and pin 24 (VFDSEN remains connected to pin 24), and instead connect pin 21 to the common pin of a SPDT switch. Then pin 24 is connected to the NC switch pin and a 10K resistor to +5V is connected to the NO switch pin.Pin 21 is the STROBE and as per the datasheet: "When STROBE is low, all Q outputs are enabled. When STROBE is high, all Q outputs are low." So, when "...all Q outputs are low" all segments and grids won't attract electrons from the filament; ie. blanking the display. This shouldn't interfere with any ongoing pin 24 activity (latching data) and once pin 21 and pin 24 are reconnected via the switch, whatever the state of the latch will be visible.SN75518FN datasheet:https://pdf1.alldatasheet.com/datasheet-pdf/view/546161/TI/SN75518FN.html

author: BarsMonster
author_rank: Contributor
timestamp: October 17, 2022, 08:28:26 am
content: Quote from: pqass on October 17, 2022, 02:16:11 amThanks for detailed answer, this will definitely help!

author: MaxFrister
author_rank: Regular Contributor
timestamp: October 18, 2022, 12:00:06 am
content: Back when this thread started, it was not possible to buy a replacement VFD for these counters.A couple of years back I bought a 53132a with a dim display. At the time I was able to buy a new made-in-China display that is working great.Price varies (I think I paid ~$120). Currently someone has one listed at ~$80 and lots of people have them listed for $200 plushttps://www.ebay.com/sch/i.html?_from=R40&_nkw=%2853131%2C53181%2C53132%29+vfd&_sacat=0&LH_TitleDesc=0&toolid=20004&mkcid=1&campid=5338192028&kw=53132+vfd&LH_PrefLoc=2&mkrid=711-53200-19255-0&_sop=15

author: RichardDiag
author_rank: Newbie
timestamp: August 14, 2023, 10:32:29 pm
content: Had someone ask me about an issue with a VFD (vacuum fluorescent display) on an HP/Agilent 33120 function generator. The issue being a dot in the ';' always being on. This suggested the driver chip, a SN75518FN was likely the issue. It also seems that several HP/Agilent equipment uses this part. Finding a replacement SN75518 was not looking good. After a few hours of searching, I did finally find two parts that appear to be possible replacement parts. I thought I would relay that info for someone else whom my be looking.It appears that Microchip HV518 and Analog Devices MAX6934 are compatible parts for the discontinued SN75518; both available from Digikey. This includes the PLCC package used in the HP/Agilent equipment.Hopes this helps someone else out there.