Test Equipment Anonymous (TEA) group therapy thread

[Cubdriver]

Been playing with 10MHz OCXO's and wanted another dedicated power supply I could run for some long term testing.  Found what looked to be a clean, late version HP 6227B (0-25v, 0-2A, dual channel) on eBay not to far from me.  This was the only test equipment item in the sellers store, so I made an offer for $75 from the $135 asking and they accepted.  Shipped fast, and very well packaged which was a pleasant surprise.  Its in better shape than I had hoped for, appears 100% original and no signs of any work.  I am seeing some ripple at max load, more so from the main channel.  The main filter bank caps do appear week, and C10 on the master regulator board needs to be replaced, but this is to be expected.  The hunt is on for some caps, but well worth it for such a nice piece of gear, they don't make things like they use to.

That thing looks almost brand new!  Nice score.  Damn you, you and evilBay just cost me more $$$! 

(Because one can never have too many power supplies, right?    )

-Pat

[0culus]

Let's play a game of "guess the waveform!" 

Something amplitude modulated with three steps, and frequency modulated with a short pulse?

-Pat

Since no one has guessed, it's a 32x1 bit LFSR. I need to try again with a slower clock though, as I think there are reflections spoiling the nice eye pattern that should result.   

[worsthorse]

Look at this. Bastard tant! The 47uf tant on the primary input to the HV oscillator. Shorted and took out the fuse. Always change this cap! 

Then he opens up an older 465 and it shows the 2 - 22uf tants in parallel. Get rid of them too.

My favorite quote from the video, "I just wonder if 'e bought these and didn't have a clue as to what 'e was talkin' about."

And good thing, too. If it weren't for folks like that, I wouldn't be able to afford the test gear I have. 

Working on the first of the TM plug-ins, the DM502. Only one tantalum to worry over; will check it before I go through the calibration procedure. I love this Tek gear. Useful simple test instruments, complete with elegant circuit design, first rate components, and useful documentation. What could be better than that?

The only kludge is the player piano selection switch, though it is still working after forty years, so who am I to judge?

[Specmaster]

Quick ethical question here. Is it morally acceptable to eviscerate a piece of HP gear which is entirely not useful for the knob caps for my 6236B, guts and the extremely nice case it comes in which will be reused for a project? HP 3551A is the device in question.

In a word YES

[worsthorse]

Quick ethical question here. Is it morally acceptable to eviscerate a piece of HP gear which is entirely not useful for the knob caps for my 6236B, guts and the extremely nice case it comes in which will be reused for a project? HP 3551A is the device in question.

* wch watching how this goes as I ponder a rack of telegraph test equipment from the 70s that I am considering tearing down because I can use the parts, case and rack mount hardware on other projects (but haven't because it is in excellent condition even if it actually useless).

[bd139]

In that case I shall lurk on that auction! I need a case and the case was working out £65, as usual more expensive than the damn contents, and this is around £32 as listed. Plus solves a number of problems I have.

[kj7e]

Found what looked to be a clean, late version HP 6227B

Is that cap really saying 80uF, 0-65VDC?      

Yeah, and that's C10 on the master reference board.  Its a common part on these supply's that needs to be replaced.  I think I will replace it with a fixed working voltage part though 

Yeah, and don't forget its brother and cousins on the same board. 
I've grown a healthy loathing for large-value axial caps over the last few years; cost on them is ducking insane, IF you can find something even reasonably close to substitute.

mnem
*Breathe... just breathe...*

If there's enough headroom I will substitute a radial cap and put shrink tubing on the leads. Done that on several of my Fluke DMM's.

I would like to keep it as close to original as possible, I'm picky that way.  Found 2 NOS Sprague 1500uF 40v snap-in's (lower caps in the rear under the main filter bank) on eBay for a fair price.  Ordered  new 12,000uF 63v United Chemi-Con the same size for the main filter bank from Mouser, going to replace the zinc plated steel 1/4" 10-32 spacers with un-plated aluminum spacers and replace the steel screws with stainless.  The zinc plating on the spacers is flaking.  Last, C9 and C10 will be replaced with 180uF 100v caps.

The only caps I know are weak are the 3000uF 40v Sprague's, anything over about 1.5 amp load and the 120Hz ripple goes up excessively.  Simply adding another good cap in parallels fixes the issue.   So another $75 in caps total, but it will look original.

[worsthorse]

I know this the wrong place to ask this question because I know what the answer will be    but...

I have an 8640B that is a bit beat up but works. In particular, the front panel is cracked in a couple of places, some of the panel lights are out, and the knobs could use some love. I haven't poked around inside or put it through my usual routine. But I am thinking, even if all I do is fix the front panel and such, I will need a parts mule, right?  Because I will get around to doing all this stuff sometime real soon. And there's this listing on ebay right now...

https://www.ebay.com/itm/152630584218

Even if I have to pay that much for shipping, am I likely to find anything less expensive that powers up, apparently, without catching on fire? I could haunt the hamfests coming up, I guess. What say you all?

And now I have to close my browser and get some work done. Right? 

[bd139]

At the very worst you'll get some leaf switches, mechanical parts and a stock of parts for it. Big chunk of the failures on these are mechanical I understand. Worst case it'll have the same broken gears as yours at which point someone sells a replacement gear kit for it!

[0culus]

I know this the wrong place to ask this question because I know what the answer will be    but...

I have an 8640B that is a bit beat up but works. In particular, the front panel is cracked in a couple of places, some of the panel lights are out, and the knobs could use some love. I haven't poked around inside or put it through my usual routine. But I am thinking, even if all I do is fix the front panel and such, I will need a parts mule, right?  Because I will get around to doing all this stuff sometime real soon. And there's this listing on ebay right now...

https://www.ebay.com/itm/152630584218

Even if I have to pay that much for shipping, am I likely to find anything less expensive that powers up, apparently, without catching on fire? I could haunt the hamfests coming up, I guess. What say you all?

And now I have to close my browser and get some work done. Right? 

Yeah, the 8640 sig gens are very solid, except for that front panel. The 8569B spectrum analyzer (as well as a few other SAs that use the same basic front panel) are the same way. Just have to be ginger with it, can't throw the controls around.

Honestly, in many cases, problems with old HP gear can be fixed by re-seating all the cards, cleaning contacts, etc.

[PrecisionAnalytic]

I'm not sure how else to work on the modules without extenders.  Figured the same for the Tektronix 7000 series.

I've been able to calibrate and adjust the attenuators on 7000 series vertical plug-ins on a 7603N by simply removing the scope's side cover and leaving the mesh screen off the plug-in.

Yep that's how you do the plugins on the Telequipment D83 also.

This may not be sufficient if you have to troubleshoot the plug-in because you can't get to the backside of the circuit board but for routine maintenance it works. The timebase plug-ins are more complex and an extender is almost mandatory but luckily they require less maintenance.

They ain't hard to make.
Below from another recent thread. IIRC I just drew the etch resist on with a ruler and permanent marker and notched it to maintain polarity like the notches in the plugin cards.

Make one, the hardest part is finding the right socket.
For the rest some old PC IDE ribbon cable and the for the plug just etch some strips on a PCB.
You could probably just do the strips with a Dremel.


One I made moons ago for the plugins for a UK Telequipment D83 (owned by Tek).

But doesn't that cause roll off in the vertical response at high frequencies? I would think that 50Mhz and above could be problematic. 

RG174 for mine and maybe better spec if working on the 1GHz modules.

[tautech]

RG174 for mine and maybe better spec if working on the 1GHz modules.

I do wonder with the speed of data that IDE cables could handle if there is need for coax at most lower frequencies.
Of course later they went to 80 conductor ribbon cables so to reduce crosstalk and these might be a better choice for higher frequencies.

[med6753]

I guess I have no ethics and my morals are questionable. I have 5 parts mules here. A Tek 465, Tek 2430, Tek DM44, Tek 7A15, and a Fluke 8800A. I have absolutely no intention of fixing any of them and they've all been scavenged for parts. My conscience is completely clear and with no lingering guilt. I am judge and jury in determining if something can be fixed and no one going to tell me different. If it goes into "no fix" it's parts.

And I'm not done sinning. If I can find a beat to crap 465B real cheap it's gonna give up it's channel 2 attenuator switch deck and go in the parts mule closet.       

[neo]

I guess I have no ethics and my morals are questionable. I have 5 parts mules here. A Tek 465, Tek 2430, Tek DM44, Tek 7A15, and a Fluke 8800A. I have absolutely no intention of fixing any of them and they've all been scavenged for parts. My conscience is completely clear and with no lingering guilt. I am judge and jury in determining if something can be fixed and no one going to tell me different. If it goes into "no fix" it's parts.

And I'm not done sinning. If I can find a beat to crap 465B real cheap it's gonna give up it's channel 2 attenuator switch deck and go in the parts mule closet.     

My stance too. If i say it's dead then it's pretty damn dead and way past the point of no return.

[med6753]

Well the new kid on the block 2430 just completed it's first successful repair. Went to power up the audio system and one of the amplifiers had a dead channel.  So I pulled the amp down to the bench and the 2430 happened to be powered up going through a burn in so it got the job. Found it in about 10 minutes. No signal on one channel through the speaker protect relay even though it's picked and the other channel is OK. I had to unsolder the relay from the board so I could get it apart. Yep, dirty contacts. Cleaned them up. Works now.  But I'm thinking of ordering a new one just in case.

No one gets a free ride here. 

[bd139]

I guess I have no ethics and my morals are questionable. I have 5 parts mules here. A Tek 465, Tek 2430, Tek DM44, Tek 7A15, and a Fluke 8800A. I have absolutely no intention of fixing any of them and they've all been scavenged for parts. My conscience is completely clear and with no lingering guilt. I am judge and jury in determining if something can be fixed and no one going to tell me different. If it goes into "no fix" it's parts.

And I'm not done sinning. If I can find a beat to crap 465B real cheap it's gonna give up it's channel 2 attenuator switch deck and go in the parts mule closet.     

My stance too. If i say it's dead then it's pretty damn dead and way past the point of no return.

On that basis, the ones in my cupboard may be parts mules and I haven't got the good ones yet

[0culus]

I guess I have no ethics and my morals are questionable. I have 5 parts mules here. A Tek 465, Tek 2430, Tek DM44, Tek 7A15, and a Fluke 8800A. I have absolutely no intention of fixing any of them and they've all been scavenged for parts. My conscience is completely clear and with no lingering guilt. I am judge and jury in determining if something can be fixed and no one going to tell me different. If it goes into "no fix" it's parts.

And I'm not done sinning. If I can find a beat to crap 465B real cheap it's gonna give up it's channel 2 attenuator switch deck and go in the parts mule closet.     

I'm kind of in the same quandary when comes to collecting 8566/68 spectrum analyzers. Would I hate to dismantle an RF unit to get parts? Yes. But, if it means another instrument can live on, I'm all for it. Probably going to have to happen to get my other 8568 running.

[med6753]

I guess I have no ethics and my morals are questionable. I have 5 parts mules here. A Tek 465, Tek 2430, Tek DM44, Tek 7A15, and a Fluke 8800A. I have absolutely no intention of fixing any of them and they've all been scavenged for parts. My conscience is completely clear and with no lingering guilt. I am judge and jury in determining if something can be fixed and no one going to tell me different. If it goes into "no fix" it's parts.

And I'm not done sinning. If I can find a beat to crap 465B real cheap it's gonna give up it's channel 2 attenuator switch deck and go in the parts mule closet.     

My stance too. If i say it's dead then it's pretty damn dead and way past the point of no return.

On that basis, the ones in my cupboard may be parts mules and I haven't got the good ones yet

Is one of them a 465B? If yes...I want the channel 2 attenuator deck.

See, I told you I have no morals. 

[tggzzz]

I guess I have no ethics and my morals are questionable. I have 5 parts mules here. A Tek 465, Tek 2430, Tek DM44, Tek 7A15, and a Fluke 8800A. I have absolutely no intention of fixing any of them and they've all been scavenged for parts. My conscience is completely clear and with no lingering guilt. I am judge and jury in determining if something can be fixed and no one going to tell me different. If it goes into "no fix" it's parts.

And I'm not done sinning. If I can find a beat to crap 465B real cheap it's gonna give up it's channel 2 attenuator switch deck and go in the parts mule closet.     

My stance too. If i say it's dead then it's pretty damn dead and way past the point of no return.

On that basis, the ones in my cupboard may be parts mules and I haven't got the good ones yet

Is one of them a 465B? If yes...I want the channel 2 attenuator deck.

See, I told you I have no morals. 

In that vein, how much are you prepared to pay?

(I have a 465 parts mule, but don't know whether ch2 deck is ok or not).

[med6753]

I guess I have no ethics and my morals are questionable. I have 5 parts mules here. A Tek 465, Tek 2430, Tek DM44, Tek 7A15, and a Fluke 8800A. I have absolutely no intention of fixing any of them and they've all been scavenged for parts. My conscience is completely clear and with no lingering guilt. I am judge and jury in determining if something can be fixed and no one going to tell me different. If it goes into "no fix" it's parts.

And I'm not done sinning. If I can find a beat to crap 465B real cheap it's gonna give up it's channel 2 attenuator switch deck and go in the parts mule closet.     

My stance too. If i say it's dead then it's pretty damn dead and way past the point of no return.

On that basis, the ones in my cupboard may be parts mules and I haven't got the good ones yet

Is one of them a 465B? If yes...I want the channel 2 attenuator deck.

See, I told you I have no morals. 

In that vein, how much are you prepared to pay?

(I have a 465 parts mule, but don't know whether ch2 deck is ok or not).

Is it a 465 or 465B? They are not the same.

[GregDunn]

I guess I have no ethics and my morals are questionable. I have 5 parts mules here. A Tek 465, Tek 2430, Tek DM44, Tek 7A15, and a Fluke 8800A. I have absolutely no intention of fixing any of them and they've all been scavenged for parts. My conscience is completely clear and with no lingering guilt. I am judge and jury in determining if something can be fixed and no one going to tell me different. If it goes into "no fix" it's parts.

And I'm not done sinning. If I can find a beat to crap 465B real cheap it's gonna give up it's channel 2 attenuator switch deck and go in the parts mule closet.     

I have a Fluke 8600A which gave its life so that two other meters could live.  And it's not worth fixing because it's now missing the ROM, DVM custom chip and some hardware - stuff you never find separately - and has at least one dodgy FET in the ADC.

[Neomys Sapiens]

Storage scopes were available well before the 24xx series. I used one in the 70s, and they weren't a new concept then.

Of course they were a pain to use, but it took a surprisingly long time for analogue storage scopes to be completely supplanted by digitising storage scopes.

Let me guess - Nicolet?

[Neomys Sapiens]

Quick ethical question here. Is it morally acceptable to eviscerate a piece of HP gear which is entirely not useful for the knob caps for my 6236B, guts and the extremely nice case it comes in which will be reused for a project? HP 3551A is the device in question.

In a word YES

I would endorse that too. I tend to pick up the most boring Tek 5000 modules, which no one wants for conversion to TM500 (with new PCB). Got 4 already below 20.-, which would be more than ok for the empty kit (which gets you an undrilled panel, but no knobs).

[tggzzz]

I guess I have no ethics and my morals are questionable. I have 5 parts mules here. A Tek 465, Tek 2430, Tek DM44, Tek 7A15, and a Fluke 8800A. I have absolutely no intention of fixing any of them and they've all been scavenged for parts. My conscience is completely clear and with no lingering guilt. I am judge and jury in determining if something can be fixed and no one going to tell me different. If it goes into "no fix" it's parts.

And I'm not done sinning. If I can find a beat to crap 465B real cheap it's gonna give up it's channel 2 attenuator switch deck and go in the parts mule closet.     

My stance too. If i say it's dead then it's pretty damn dead and way past the point of no return.

On that basis, the ones in my cupboard may be parts mules and I haven't got the good ones yet

Is one of them a 465B? If yes...I want the channel 2 attenuator deck.

See, I told you I have no morals. 

In that vein, how much are you prepared to pay?

(I have a 465 parts mule, but don't know whether ch2 deck is ok or not).

Is it a 465 or 465B? They are not the same.

Oh, <expletive deleted>. I have a 465B as well, but I'm not yet prepared to declare that a parts mule, since there is some life in it.

Sorry to have got your hopes up.

[tggzzz]

I guess I have no ethics and my morals are questionable. I have 5 parts mules here. A Tek 465, Tek 2430, Tek DM44, Tek 7A15, and a Fluke 8800A. I have absolutely no intention of fixing any of them and they've all been scavenged for parts. My conscience is completely clear and with no lingering guilt. I am judge and jury in determining if something can be fixed and no one going to tell me different. If it goes into "no fix" it's parts.

And I'm not done sinning. If I can find a beat to crap 465B real cheap it's gonna give up it's channel 2 attenuator switch deck and go in the parts mule closet.     

I have a Fluke 8600A which gave its life so that two other meters could live.  And it's not worth fixing because it's now missing the ROM, DVM custom chip and some hardware - stuff you never find separately - and has at least one dodgy FET in the ADC.

I have a Solartron 7075 like that; the remnants are "in storage". No ROM, of course, since there's no processor - just 7.5 panaplex digits and trimpots.