Test Equipment Anonymous (TEA) group therapy thread

[Ice-Tea]

It is, but our politicians actually tell us that this is the real deal. The green party being ideologically sound is telling us that the electricity is coming from the grid and they have a ought kobolds to not worry about any battery issues.

Ah, yes, the green wunderkindren. Over here (with 50% nuclear electricity) they've decided to close all nuclear plants and push to an all electric car park.. They nuclear energy is to be replaced by spit, paperclips and a prayer.

[Ice-Tea]

Some update on the fine Belgian TEA:...

*snip*

Accidently, I have a working one as well. So, if you get stuck and want to do a comparison or swap party...

Are those tants all over the place? Bleh..

[bd139]

Ok this 8050A is naaasty. It looks like the PSU is hosed. I can get the CPU up but it displays P.PPPP if I bring that up on its own so that doesn't look totally toast.

So far:

- transformer is toast
- power supply wont run
- cpu does come up. analogue side unknown at this point.

Big risk is the -10v rail which may have hit -20v.

Shelving it until my PL320 arrives.

[McBryce]

So my "Fixer-upper through sheer boredom" just turned up. It's a Racal Dana 9904 that I picked up for €26. A bit dirty, but it's all there and doesn't look like anyone has tried to fix it so far. It powers up, but doesn't count. Lots of retro goodness inside and no custom IC's. There's a nice ovenised 5MHz source inside that I can use even if the device isn't fixable.

McBryce.

Ok, so there is a semi-custom part inside and as Murphy would have predicted, it's the bit that's broken. I don't suppose anyone here has a working Ferranti 22-4601 spare that they'd be willing to sell me?

McBryce.

[factory]

hey med

when equipped with just a plain jane crystal those counters shift a little when you take the cover off.  if fitted with an ocxo it is not a problem.

am betting that it will improve if you just put the top back on. 

if you still need to adjust it, the trimmer cap is accessible thru one of the vent holes.  oh.....don't use a screwdriver or you will go crazy as the set point changes when you withdraw the shaft.  hopefully you have a really small diddle stick.


good luck.


ps  ok children.  don't start any nonsense.  we all know what a diddle stick is.

That one is new enough to have the space to fit the OXCO connector, I have a older HP 5326B with the crystal board fitted next to the right-hand case side, not enough room for the OCXO, hence they redesigned the mainboard.
Mine has problems the display not resetting before the next count (also affects the DVM input), currently waiting in the repair queue too.






David

[BU508A]

Ok this 8050A is naaasty. It looks like the PSU is hosed. I can get the CPU up but it displays P.PPPP if I bring that up on its own so that doesn't look totally toast.

So far:

- transformer is toast
- power supply wont run
- cpu does come up. analogue side unknown at this point.

Big risk is the -10v rail which may have hit -20v.

Shelving it until my PL320 arrives.

Good luck with the repair of that one.
Can you replace the transformer easily or is some special unobtainium part?

[GreyWoolfe]

Yaesu menus were bloody awful. I wouldn’t blame that on your brain 

That is why I have an FT-1000 MP.  NO MENUS 

[bd139]

Ok this 8050A is naaasty. It looks like the PSU is hosed. I can get the CPU up but it displays P.PPPP if I bring that up on its own so that doesn't look totally toast.

So far:

- transformer is toast
- power supply wont run
- cpu does come up. analogue side unknown at this point.

Big risk is the -10v rail which may have hit -20v.

Shelving it until my PL320 arrives.

Good luck with the repair of that one.
Can you replace the transformer easily or is some special unobtainium part?

You can get a replacement for £25 but it looks like the -10v tail was overvolted which is bad juju on the analogue front. That is directly derived from proportional mains voltage so kapoof.

As much as I want to throw the time into this one it’s a big and expensive project. I’ve verified that the CPU and display work nicely so I’m going to just bounce it honestly as a set of plastics and a new display module. There are plenty of working ones with knackered displays and plastics and this would be a fine set of parts for them. 100% the best outcome.

[Kosmic]

Enjoy. I was considering one of them myself before I decided to bail out. FT817 needs to die.

Yeah sure, you're done with Ham right ? 

[bd139]

100%. Ranks below my ex on things I’ll go near again

[med6753]

Enjoy. I was considering one of them myself before I decided to bail out. FT817 needs to die.

Yeah sure, you're done with Ham right ? 

Yep, just like he was done with Tek's. 

[Kosmic]

100%. Ranks below my ex on things I’ll go near again

So you take the ex back and then go back to Ham ?  sound like a plan 

[capt bullshot]

Some update on the fine Belgian TEA:...

*snip*

Accidently, I have a working one as well. So, if you get stuck and want to do a comparison or swap party...

Are those tants all over the place? Bleh..

By the looks, yes, Philips labelled. And blue Philips electrolytics (more bleh ...). Anyway, the power supplies look fine, so for the moment I'll ignore them.

Edit: BTW - the IEC mains connector is Schaffner branded. Rifa timebombs inside?

[Kosmic]

Anybody fixed a DSLR in the past ?

My Canon 5D just died. Don't want to power up anymore. I was watching some disassembly videos and man it look like it's a pain. They are normally super complex with tons of screws and mechanical parts.

I'm wondering if I should try a repair or simply put it on ebay sold as-is/forparts.

[factory]

Edit: BTW - the IEC mains connector is Schaffner branded. Rifa timebombs inside?

I opened up one of the Schaffner connectors from my Tek scopes & found two WIMA MP3 capacitors instead, these are also paper based. The markings were missing from the white capacitor.

David

[bd139]

Anybody fixed a DSLR in the past ?

My Canon 5D just died. Don't want to power up anymore. I was watching some disassembly videos and man it look like it's a pain. They are normally super complex with tons of screws and mechanical parts.

I'm wondering if I should try a repair or simply put it on ebay sold as-is/forparts.

A friend of mine tried to repair his. He’s a mechanical engineer. Said he’d never do it again. He repaired it but the self cal/test process didn’t pass after he spent £100 on it. This was one motivation to sell my old DLSR 

[McBryce]

Anybody fixed a DSLR in the past ?

My Canon 5D just died. Don't want to power up anymore. I was watching some disassembly videos and man it look like it's a pain. They are normally super complex with tons of screws and mechanical parts.

I'm wondering if I should try a repair or simply put it on ebay sold as-is/forparts.

I repaired a Canon 350D a few years ago, when the USB connector stopped working (broken solder joints). Never again! On the upside though, I had 6 tiny screws left over after I was finished for my spares bin. Tip: Take lots of photos (with a different camera) as you disassemble it.

McBryce.

[Kosmic]

Anybody fixed a DSLR in the past ?

My Canon 5D just died. Don't want to power up anymore. I was watching some disassembly videos and man it look like it's a pain. They are normally super complex with tons of screws and mechanical parts.

I'm wondering if I should try a repair or simply put it on ebay sold as-is/forparts.

A friend of mine tried to repair his. He’s a mechanical engineer. Said he’d never do it again. He repaired it but the self cal/test process didn’t pass after he spent £100 on it. This was one motivation to sell my old DLSR 

Ok thanks. Exactly what I thought. It's going on the bay.

[Wolfgang]

Do have a look at the Keysight app note and web calculator, its well explained there.

I'm probably being dense because I'm tired, but what Keysight app note?

He is probably referring to
5952-3706 Y-Factor Method for Noise Figure Measurement Accuracy
or
5952-8255 Fundamentals of RF and Microwave Noise Figure Measurements
or
5980-0288 10 Hints for Making Successful Noise Figure Measurements

That web calculator is probably the same as the enclosed excel-sheet. Can't attach it, too large.
Look for NFUC2017* at Keysight.

Thanks.

The original points, now snipped, were not about noise figure. I agree Wolfgang's points are correct when measuring noise figure, but I don't think they are when using a noise source as a poor man's tracking generator. If I'm wrong, I'd like to be enlightened

For NF measurements *in general* the S11 of the source is critical. As long as the DUT has reasonable gain and not too low NF, all is swell.
If you have a DUT with extremely bad match but extremely low noise figure (like GaAs FET amps...) noise energy coming *out* of the DUT input will be reflected by the noise source if its output impedance is not exatcly 50Ohms, making results incorrect.

Remedy:
- Noise measurement with vector correction (cold source technique) as available in the Keysight PNA-X series ($$$).
  Then you need an extra well characterized noise source.
- stay away from highly mismatched amps if you can, because in a lot of cases they are unstable as well.
  0.1dB noise figures are, in a lot of cases, a marketing hype with no practical benefit. A few 10cm of cable at VHF/even less at UHF and your advantage is gone.

[tggzzz]

Edit: transformer is melted 

Fortunately nowadays 240Vac->xVdc SMPSs are small and cheap. I used that trick on one of my Tek 1502s, and pointed it out when I flogged it.

Wouldn't help with the s/-10V/-20V/g, though.

[mnementh]

hey med   when equipped with just a plain jane crystal those counters shift a little when you take the cover off.  if fitted with an ocxo it is not a problem.   am betting that it will improve if you just put the top back on.  if you still need to adjust it, the trimmer cap is accessible thru one of the vent holes.  oh.....don't use a screwdriver or you will go crazy as the set point changes when you withdraw the shaft.  hopefully you have a really small diddle stick.

good luck.

ps  ok children.  don't start any nonsense.  we all know what a diddle stick is.

mnem
 

[mnementh]

hey med   when equipped with just a plain jane crystal those counters shift a little when you take the cover off.  if fitted with an ocxo it is not a problem.   am betting that it will improve if you just put the top back on.  if you still need to adjust it, the trimmer cap is accessible thru one of the vent holes.  oh.....don't use a screwdriver or you will go crazy as the set point changes when you withdraw the shaft.  hopefully you have a really small diddle stick.

good luck.

ps  ok children.  don't start any nonsense.  we all know what a diddle stick is.

Turns out it was 6Hz off with cover off and on. Surprisingly it made no difference.  I have lots of diddle sticks. 

Edit...I saw that trimmer cap but wasn't sure if it was for the counter or perhaps the DVM so I wanted to check the manual first. I didn't want to monkey around and twiddle with the diddle until I was sure of what I was diddling. 

Remember... it's a combination that works best; the twiddle of the diddle AND the angle of the dangle AND the motion of the ocean ALL TOGETHER... THAT is what'll make 'er purr.

mnem
Be proud of me; I said all that with a perfectly straight face.

[ch_scr]

I won't be in Discord this evening, picture related. Barbeque party at colleague from work. Have fun!

[mnementh]

Some update on the fine Belgian TEA:      It's alive and at least does something but showing the E4 message:

So the normal eevblog member would follow the "don't turn it on, take it apart" workflow. For some particular reasons (basically because I'm curious), I decided to turn it on before I take it apart. Nothing happened, the display was blank, some LEDs were lit at the front panel. Randomly pushing and turning buttons and knobs revealed this:

(SNIP lots of really insightful exposition, just for brevity's sake )   ...Now, with Hold Off turned on, the counter actually shows plausible frequency measurements up to around 200kHz. Above its garbage.   This is another hint the COAC most probably is fine, but the CEX board might be faulty, as this acts as a prescaler and high resolution extension to the COAC.

See some preliminary teardown pictures here:
http://wunderkis.de/pm6654/teardown/

Started a new thread in the repair area:
https://www.eevblog.com/forum/repair/philips-pm6654/msg3142792/

Some excellent deductive reasoning there, Detective. Well played!  We look forward to the results when you come to a contusion on it's ultimate ailment!

mnem
 

[Specmaster]

Ok this 8050A is naaasty. It looks like the PSU is hosed. I can get the CPU up but it displays P.PPPP if I bring that up on its own so that doesn't look totally toast.

So far:

- transformer is toast
- power supply wont run
- cpu does come up. analogue side unknown at this point.

Big risk is the -10v rail which may have hit -20v.

Shelving it until my PL320 arrives.

Thats real bad luck, did you get that 8050A from same seller as the other one you posted about?