Test Equipment Anonymous (TEA) group therapy thread

[tggzzz]

At a recent hamfest I picked up an hp651b oscillator cheaply; 10Ha-10MHz, 90dB attenuator, 300µV-3Vrms.

For amusement, what do you think the spec is of that original 80mm long electrolytic just above the orange cap inserted by a previous owner? I've unhelpfully obscured the µF/V specs with the green/red scribble, since I've never seen one like it before.

OK, here it is:





Anybody else seen a 1V electrolytic?

[bd139]

I’m surprised they used an electrolytic for that. They had much better film capacitors back then. About 5-6 of them would probably be a better bet.

[Specmaster]

Later than I'd hoped, but here at last are the photos of the TTi SM630, it is just as if it had just been made at the factory, inside and out. Needs a little cleaning on the case, but thats to be expected. Going by the date code on the chips, and there are many of them, this was made in 1994 or later. The backup battery looks new and judging by the soldering on the back of the board, those three connections are all new and shiny, unlike the others which have that aged dull appearance.

I have run the scope through its paces using the Heathkit IG4505 calibrator, and it hits the right frequency and periods as per calibrator, so no wuckers there. Multimeter part also meets the requirements, agreeing with both the AD584-M but also the current ratings against the Mastech MS7221 calibrator and the frequency counter is pretty much on the money too.

The backlight, as already mentioned in a previous post, is useless. It is one of those reflective types with a white panel and maybe unobtainuim, will speak to TTi about this aspect. If it is as I suspect, unrepairable, then it really becomes a SM620 which never had a backlight anyway.

I'll have to do the function generator in another post.

Nice bit of kit that. I want one now 

The display is an Optrex DMF697. EL backlight. Looks like you can get replacements for about £8 on eBay 

https://www.ebay.co.uk/itm/Optrex-DMF697-equivalent-part-Graphic-LCD-Display-Module-128x64-/284139570122

Yeah, good luck with finding one of them, that was the first time I have seen one, in fact I never knew that TTi even made them  They made 3 variants, SM610, SM620 and the SM630, data sheet is attached, it even does data logging among its many features. Reading the spec sheet, this was a pretty advanced piece of kit back in the day and was clearly aimed at the professional user.

Thanks for the info on that display, I see that they replaced the dedicated chip set for cobs on the newer unit, but I think I need to measure the supply going to EL1 and EL2speak to TTi before ordering one as I suppose it might be the driver that is faulty? While I'm there, I'll see if they have copies of the user and service manuals as well.

[dl6lr]

Those orange capacitors are Tants in disguise  , had remand short circuit related failures in a PSU from a rail related bit of kit at work.

Yes, already replaced two of them. In all of those PSU I got, the same tant was shorted (and only that one). That is the one for the -40V with the LM237H (already missing here as it was toast).

[bd139]

Later than I'd hoped, but here at last are the photos of the TTi SM630, it is just as if it had just been made at the factory, inside and out. Needs a little cleaning on the case, but thats to be expected. Going by the date code on the chips, and there are many of them, this was made in 1994 or later. The backup battery looks new and judging by the soldering on the back of the board, those three connections are all new and shiny, unlike the others which have that aged dull appearance.

I have run the scope through its paces using the Heathkit IG4505 calibrator, and it hits the right frequency and periods as per calibrator, so no wuckers there. Multimeter part also meets the requirements, agreeing with both the AD584-M but also the current ratings against the Mastech MS7221 calibrator and the frequency counter is pretty much on the money too.

The backlight, as already mentioned in a previous post, is useless. It is one of those reflective types with a white panel and maybe unobtainuim, will speak to TTi about this aspect. If it is as I suspect, unrepairable, then it really becomes a SM620 which never had a backlight anyway.

I'll have to do the function generator in another post.

Nice bit of kit that. I want one now 

The display is an Optrex DMF697. EL backlight. Looks like you can get replacements for about £8 on eBay 

https://www.ebay.co.uk/itm/Optrex-DMF697-equivalent-part-Graphic-LCD-Display-Module-128x64-/284139570122

Yeah, good luck with finding one of them, that was the first time I have seen one, in fact I never knew that TTi even made them  They made 3 variants, SM610, SM620 and the SM630, data sheet is attached, it even does data logging among its many features. Reading the spec sheet, this was a pretty advanced piece of kit back in the day and was clearly aimed at the professional user.

Thanks for the info on that display, I see that they replaced the dedicated chip set for cobs on the newer unit, but I think I need to measure the supply going to EL1 and EL2speak to TTi before ordering one as I suppose it might be the driver that is faulty? While I'm there, I'll see if they have copies of the user and service manuals as well.

You should be able to check the output of the driver with a DMM. Around 120-240v AC peak to peak.

Edit: Driver, assuming it’s that red transformer transistor and cap looks like a simple converter. Should be easy to replace or fix.

[Specmaster]

Yeah, it could just be that bastard tant failing grrr.

[bd139]

Possibly. Fun working it out though 

Got to say I still really like how that era and later TTi stuff was constructed. It’s nice to work on.

As I’m off work for a few days it’s project time. Have replaced the RIFA in the E3630A this morning so that’s ready to roll. Next one is work out the HP 5381A. Seems to be working fine after cleaning the switches up. I have it hooked to channel 2 output on the Tek 475 at the moment. Will poke the spare CTI OCXO I have lying around on it next.

[Specmaster]

Now for the second item in my TEA gathering quest, the function generator by Feedback Ltd, the FG600. This again, like the SM630, almost looks as if it was just taken out of the box, inside and out, the outside just needs a quick wipe down to remove a few spots of dirt, and it will be pristine gain. Inside it is perfect looking and dead easy to repair, the clamshell case is removed and leaves the circuit board supported by the front and back panels and some clever brackets, I wonder why this method is not used any more? Dating was pretty easy, there being only 3 IC's on the board, all made in 1974, so I'm assuming that is the era when it was made, although it might be later and used up old chips?

As mention in a previous post, those 4 Sprague caps (470uF) actually now measure around 500uF with an ESR of .4 ohms each, so they seem to be OK and will staying I think. If 1974 is the correct date of manufacture, then that might explain why it seems impossible to obtain copies of the user and service manuals as this would have predated the internet as well as PDF copies, but the company does still seem to around so a long shot, but they may have paper based copies and be willing to scan them for me?

[Robert763]

Tek "bundle" on ebay UK.
www.ebay.co.uk/itm/274893611223
Seller has been listing a bit of TE recently but seems a bit pricey.

[bd139]

Yeah saw that one. At that price, nope!

@Specmaster: nice. I’ve never seen inside one of them. Seems to be standard bits which is good 

Just doing full check out on 5381a and some RTFM and this is actually a really nice counter. Despite having only 7 digits it has a nice overflow system so you can use it down to 0.1Hz resolution at 80MHz.   It it appears the decimal points on KHz and Hz are not working though. So some debugging required. These are dumb switched ones so I reckon it’s the front panel switch or LEDs which have failed. Someone has already replaced three of the displays so may be related. At least I’ve got something to do now!

[Specmaster]

@bd139, just stripped down the SM630 and measured the supply on EL1 and EL2, and it is 79Vac. Looked at the tant, it is a 4uF 16V and I'm getting a reading of 4.7uF and just 650mV across it, that seems a bit low to me.

[mnementh]

A little online research revealed this article from ELEKTOR; I actually recognized the diagram from a discussion I read some while back on another random trawl. More research found a number of fleaBay listings for probes based on the design, and for the ~$8 difference between it and just getting the parts I didn't have on hand, I let laziness prevail and picked the one with the most positive feedback which was also one of the least expensive.

   ...

Interesting, he fixed his design (60dbm). You have an url for the blue one ? I only see the old green one on ebay. The input capacitor on the green one is not implemented correctly. So it doesn't really go higher than 500MHz.

I posted about it over here https://www.eevblog.com/forum/testgear/hi-z-probe-for-50-ohm-spectrum-analyzer/msg3220350/#msg3220350

I was surprised myself to see the board not only different color but redesigned, tho I didn't look too deeply into the differences.

The listing I bought from is here: https://www.ebay.com/itm/332393676082

It still shows the green ones. This one is decent enough quality 1.6mm FR4. 

mnem
*toddles over to scope out that post*

Why didn't you just power it with USB mnem ?

Noise, ~7V dropout voltage, wanted to keep the power source completely isolated/integrated for playing with my battery-op toys. I'm already thinking of subbing an ultra-low noise LDO like a TPS79101/TPS79147 to get a little more battery life and maybe drop noise floor as discussed in the associated thread.

mnem
 

mnem
also, maybe I was being just a leetle beet too clever for my own good.

[bd139]

@bd139, just stripped down the SM630 and measured the supply on EL1 and EL2, and it is 79Vac. Looked at the tant, it is a 4uF 16V and I'm getting a reading of 4.7uF and just 650mV across it, that seems a bit low to me.

Possible. Did you check it open circuit ie unplug the display? The display might be pulling to down.

[bd139]

Yeah saw that one. At that price, nope!

@Specmaster: nice. I’ve never seen inside one of them. Seems to be standard bits which is good 

Just doing full check out on 5381a and some RTFM and this is actually a really nice counter. Despite having only 7 digits it has a nice overflow system so you can use it down to 0.1Hz resolution at 80MHz.   It it appears the decimal points on KHz and Hz are not working though. So some debugging required. These are dumb switched ones so I reckon it’s the front panel switch or LEDs which have failed. Someone has already replaced three of the displays so may be related. At least I’ve got something to do now!

Well it didn’t take a long time to work out the problem with the counter decimal point. The idiot who replaced the right three displays put the wrong ones in  . Have attached the utterly annoying disparity.

I’ve located the data sheet for the original part (5082-7731) and located a suitable replacement (Kingbright SA03-11RWA). Now thinking if I should do all 7 or just the wrong three.

[BU508A]

Yeah saw that one. At that price, nope!

@Specmaster: nice. I’ve never seen inside one of them. Seems to be standard bits which is good 

Just doing full check out on 5381a and some RTFM and this is actually a really nice counter. Despite having only 7 digits it has a nice overflow system so you can use it down to 0.1Hz resolution at 80MHz.   It it appears the decimal points on KHz and Hz are not working though. So some debugging required. These are dumb switched ones so I reckon it’s the front panel switch or LEDs which have failed. Someone has already replaced three of the displays so may be related. At least I’ve got something to do now!

Well it didn’t take a long time to work out the problem with the counter decimal point. The idiot who replaced the right three displays put the wrong ones in  . Have attached the utterly annoying disparity.

I’ve located the data sheet for the original part (5082-7731) and located a suitable replacement (Kingbright SA03-11RWA). Now thinking if I should do all 7 or just the wrong three.

Why is the first display upside down (in respect to its neighbours)?

[bd139]

Yeah saw that one. At that price, nope!

@Specmaster: nice. I’ve never seen inside one of them. Seems to be standard bits which is good 

Just doing full check out on 5381a and some RTFM and this is actually a really nice counter. Despite having only 7 digits it has a nice overflow system so you can use it down to 0.1Hz resolution at 80MHz.   It it appears the decimal points on KHz and Hz are not working though. So some debugging required. These are dumb switched ones so I reckon it’s the front panel switch or LEDs which have failed. Someone has already replaced three of the displays so may be related. At least I’ve got something to do now!

Well it didn’t take a long time to work out the problem with the counter decimal point. The idiot who replaced the right three displays put the wrong ones in  . Have attached the utterly annoying disparity.

I’ve located the data sheet for the original part (5082-7731) and located a suitable replacement (Kingbright SA03-11RWA). Now thinking if I should do all 7 or just the wrong three.

Why is the first display upside down (in respect to its neighbours)?

This is so that the thing can display an overflow indicator at the top left that can’t be confused with a decimal point. So if you’re in KHz range and it overflows 999.999,9 KHz then it will light up to say it has trimmed the MSD off.

[Specmaster]

@bd139, just stripped down the SM630 and measured the supply on EL1 and EL2, and it is 79Vac. Looked at the tant, it is a 4uF 16V and I'm getting a reading of 4.7uF and just 650mV across it, that seems a bit low to me.

Possible. Did you check it open circuit ie unplug the display? The display might be pulling to down.

Yeah I did that and the voltage dropped to 415mV, I'm leaning towards the transistor here.

With your display, I'd be inclined, assuming you're keeping it to get all 7 just swap out the 3 for now, then you'll have some spares otherwise if they fail later you bet your life that they won't be available then any more.

[bd139]

@bd139, just stripped down the SM630 and measured the supply on EL1 and EL2, and it is 79Vac. Looked at the tant, it is a 4uF 16V and I'm getting a reading of 4.7uF and just 650mV across it, that seems a bit low to me.

Possible. Did you check it open circuit ie unplug the display? The display might be pulling to down.

Yeah I did that and the voltage dropped to 415mV, I'm leaning towards the transistor here.

With your display, I'd be inclined, assuming you're keeping it to get all 7 just swap out the 3 for now, then you'll have some spares otherwise if they fail later you bet your life that they won't be available then any more.

Possibly gone low beta after being abused for a while so worth a try. Else replace display I reckon.

Apparently bitsbox sell the Kingbright parts so a full replacement set of them is £7.70. I’m just checking which parts they ship out now with them via email. Might as well do the lot while I’m in there. The original displays are prone to failure as they were fairly early LED products. They’re a completely standard display as long as you don’t go chasing HP original parts.

[factory]

Those gold plated pins & sockets look a lot like those found in 1980's Tek oscilloscopes, in fact I was looking at some earlier in the Tek 214* at work.

You have missed the Telfon? insulated pin & blue socket, to the right of the row of pins/sockets, HP/Dymec seem to use the same in some voltmeters, the 2402A has quite a few and I've yet to identify something to use to make jumper wires top go with the standard extender board (of course the original custom extenders are complete unobtainium  ).

The blue pins and sockets appear to only  locate the board and provide mechanical stabilty.     I'll double check next time I have the cards out.   

The other sockets allow for some misaligment of the pins.    The blue pins and sockets do not.


'Dupont' leads might work.  I don't have enough on hand to try.   I just ordered  several types from Amazon.

Have another look at the manual.

Now I'm back from work, I've just downloaded the 5100AF pdf & looked through the pages for the reference/isolator board, which I think is the one in your picture. 
The blue connectors are labelled 1 & 24 and the next two pages of circuits show them being used,1 is labelled BSV (what ever that is?) & 24 is the +10V Ref for the ohms range.

David

[factory]

At a recent hamfest I picked up an hp651b oscillator cheaply; 10Ha-10MHz, 90dB attenuator, 300µV-3Vrms.

For amusement, what do you think the spec is of that original 80mm long electrolytic just above the orange cap inserted by a previous owner? I've unhelpfully obscured the µF/V specs with the green/red scribble, since I've never seen one like it before.

OK, here it is:





Anybody else seen a 1V electrolytic?

Have quite a few hp 3400A voltmeters here, they use a 880uF at 1V on the chopper board.
The one shown is from an early design of the board, it's what would have been fitted to the mid 1960's 3400A I bought from BD (linked from the first page of the TEA thread). Of course they aged badly and most got replaced by later redesigned boards, with the smaller chopper assembly, or later still IC based version.



The non-polarised capacitor I mentioned last night was a 300uF at 10V from a hp 209A oscillator, I think it has similar dimensions as the cap from the 651B though.


David

[Andrew_Debbie]

[
Have another look at the manual.

Now I'm back from work, I've just downloaded the 5100AF pdf & looked through the pages for the reference/isolator board, which I think is the one in your picture. 
The blue connectors are labelled 1 & 24 and the next two pages of circuits show them being used,1 is labelled BSV (what ever that is?) & 24 is the +10V Ref for the ohms range.

David

You are right.  Missed that.  BSV is the bootstrap common.       The 5100 and and 5100AF reference/Isolator cards (J5) are slightly different.  I'll have to look at the PCB and double check the blue pins do the same thing.  They almost certainly do.


  I think the 5100 and 5100AF digitiser cards (J3) use the same PCB but there is at least one component difference.    J3- 1 is  HV buffer in.  J3-30 is REF GND.

[mnementh]

Today's Project: Cheap RF Active Probe      https://a360.co/37CE8El   

...Next on the agenda will be to do some testing, once I find appropriate adapters. Maybe I'll faff around with it on my TinySA/nanoVNA as well. 

And maybe I should add a probe cover; that little fucker is poky! 

Woke up at 6AM; this was stomping around the back of my head like Tim Curry in knee-high boots  and wouldn't let me go back to sleep.

Now printing; due to hollow spaces, it actually needed to be printed vertical orientation. Should be interesting; I probably screwed up at least 3 things on it, as I didn't even make my coffee until the file was done and printer warming up. 

mnem
"I'm weak... and what's wrong with that...?
Boy, oh boy I love it when I fall for dat..."

[factory]

Some cheap boat anchor TEA for those in the US, including the hp 2590A from a few weeks back, several microwave amplifiers, a RF signal gen and a few TV waveform monitors. All reduced to $10 start price.

https://www.ebay.com/sch/Test-Measurement-Inspection/181939/m.html?_ssn=elizha35&_from=R40&_nkw=

If that 2590A was over here I would have bid.


David

had been watching that 2590 transfer oscillator at 50 bucks for a couple of weeks.   then saw it go to an auction starting at 10.  was gonna wait till the last second and steal it just to have something cub does not already have.  (because who in the world would be watching for a POS like that).

but then SOMEONE had to announce it to the only crowd on planet earth who are compulsive enough to actually bid on it.

you have almost pushed me to the point of crowing about tossing tea in the harbor. 

am consoled by the fact that on sunday morning i stole a 5256a hetrodyne converter from a hobo for 20 bucks.

I didn't think anyone was interested, as I mentioned it over a month ago when it was $25, or maybe I missed the replies.  The B version sold pretty quickly.
https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg3597532/#msg3597532

I've now got to confess after last nights post, I asked about shipping and it now has an international option added. 

David

did not notice your previous post.  probably because there was no picture of the transfer oscillator? 

just noticed that when it was posted for $50 buy it now....the shipping was about $35.  now that it is on auction starting at $10 the shipping is $50.

would have bought it at $25.   that's the way it goes.   ya' snooze, ya' lose.

(if the international shipping is not too horrendous and you really want it ......i will restrain myself and step back)

The post probably got lost amongst the non-TEA stuff, only adding a pic of the Wavetek X/Y display probably didn't help. 

Yes I'm interested in the 2590A, shipping isn't too bad either.

David

[mnementh]

Yeah saw that one. At that price, nope!

@Specmaster: nice. I’ve never seen inside one of them. Seems to be standard bits which is good 

Just doing full check out on 5381a and some RTFM and this is actually a really nice counter. Despite having only 7 digits it has a nice overflow system so you can use it down to 0.1Hz resolution at 80MHz.   It it appears the decimal points on KHz and Hz are not working though. So some debugging required. These are dumb switched ones so I reckon it’s the front panel switch or LEDs which have failed. Someone has already replaced three of the displays so may be related. At least I’ve got something to do now!

Well it didn’t take a long time to work out the problem with the counter decimal point. The idiot who replaced the right three displays put the wrong ones in  . Have attached the utterly annoying disparity.

I’ve located the data sheet for the original part (5082-7731) and located a suitable replacement (Kingbright SA03-11RWA). Now thinking if I should do all 7 or just the wrong three.

As you're replacing them all... may as well go green (maybe emerald green... I'm really liking that color LED right now) and make it unique provided the lens is smoked some compatible color. I'd suggest royal blue (they're making them now too), but that would just be asking folks to line up and me...

Ehhh... the colors I'm thinking of are much higher intensity at the specified 10mA drive current. Just ignore me; I'm fulminating at the mind again.

mnem
 

[nixiefreqq]

Some cheap boat anchor TEA for those in the US, including the hp 2590A from a few weeks back, several microwave amplifiers, a RF signal gen and a few TV waveform monitors. All reduced to $10 start price.

https://www.ebay.com/sch/Test-Measurement-Inspection/181939/m.html?_ssn=elizha35&_from=R40&_nkw=

If that 2590A was over here I would have bid.


David

had been watching that 2590 transfer oscillator at 50 bucks for a couple of weeks.   then saw it go to an auction starting at 10.  was gonna wait till the last second and steal it just to have something cub does not already have.  (because who in the world would be watching for a POS like that).

but then SOMEONE had to announce it to the only crowd on planet earth who are compulsive enough to actually bid on it.

you have almost pushed me to the point of crowing about tossing tea in the harbor. 

am consoled by the fact that on sunday morning i stole a 5256a hetrodyne converter from a hobo for 20 bucks.

I didn't think anyone was interested, as I mentioned it over a month ago when it was $25, or maybe I missed the replies.  The B version sold pretty quickly.
https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg3597532/#msg3597532

I've now got to confess after last nights post, I asked about shipping and it now has an international option added. 

David

did not notice your previous post.  probably because there was no picture of the transfer oscillator? 

just noticed that when it was posted for $50 buy it now....the shipping was about $35.  now that it is on auction starting at $10 the shipping is $50.

would have bought it at $25.   that's the way it goes.   ya' snooze, ya' lose.

(if the international shipping is not too horrendous and you really want it ......i will restrain myself and step back)

The post probably got lost amongst the non-TEA stuff, only adding a pic of the Wavetek X/Y display probably didn't help. 

Yes I'm interested in the 2590A, shipping isn't too bad either.

David

ok, fair enough.  am standing down.

if someone snipes you......it was not me.

good luck (and we are looking forward to pictures of whatever magic microwave bits are inside).