Test Equipment Anonymous (TEA) group therapy thread

[kj7e]

I forgot to add, I have an external PCTEL GPS Timing antenna which does a great job with the L1 signal, but not so well with the other GNSS systems, like Galileo and GLONASS.  Galileo is what I'm really after as it has the potential to provide a much greater accuracy than GPS.  The M8T with the latest firmware is enabled for Galileo and BeiDou, can track three constellations and up to 32 sats at once, I'm seeing up to 20 now just with my L1 antenna.  I placed an order for a GNSS multiband external PCTEL antenna.  The M8T has a Survey-In Time Mode that computes a fixed position then sets it.  This helps by taking out relative motion in the timing factors. 

[bd139]

At least we're not in the era of Selective Availability on GPS and nothing else up there!

Not looked at Galileo other than them annoying the 23cm band users yet. Plus AFAIK we're excluded from it when we bail out of Europe or something. Not sure what the consequences there are from a technical perspective other than wasted investment.

Just looking through the 5334B schematics and I'm going to bring the +15V unregulated line out to a connector on the back. This is rectified and smoothed when the unit is plugged in and turned off to power the reference in standby mode so I will then make a patch lead so the 5334B can power its external reference. Job done. Also saves using an SLA and wall wart which is the current power supply for this!

This is definitely the start of time nuttery. There I've said it. I've found my nuttery niche! 

[mnementh]

Okay... so what time is it? 

mnem
Relatively, of course. 

[Kosmic]

Got 2 new power supplies for the bench last week. Got them pretty cheap since they were sold as broken. They both goes up to 40V which is interesting since the 2 power supplies I already have are limited to 20V.



The big one on the left (Lambda LQ-532) had a binding post broken but otherwise was supposed to be functional.



The other one (Lambda LQD-422) was showing impossible number on the meter (84V ) and the seller mentioned that it was not possible to set the voltage correctly.



So I serviced both unit. Changing most of the smaller electrolytic cap (the big one were fine and they are not easy to find anyway).  Since those unit can be disassembled quite easily changing the binding post on the LQ-532 was a piece of cake.




I also took the time to clean the Meter Selection switch with deoxit on both units. On those models the switch tend to get dirty and then the meter give false reading.



After all that work they are both happily humming along with my other Lambda PSU (I got 4 now  )

[mnementh]

Mmm.... juicy! Well done! 

eBay auction: #133017269362

mnem
*time for a little moose juice and relax*

[bitseeker]

Nicely done. There's something about that era of Lambda power supplies that I like, but don't yet own any. I'll have to fix that at some point.

And now, for something completely different. A mechanical frequency meter/monitor:

[kj7e]

Just got done cleaning up and checking out my new (to me) HP 3310B Function Generator.  I'm starting to see a theme here.

[battlecoder]

Well done.
Those supplies look great.
Now I feel like I need proper power supplies.

Just got done cleaning up and checking out my new (to me) HP 3310B Function Generator.  I'm starting to see a theme here.

Gorgeous set!

[beanflying]

Just got done cleaning up and checking out my new (to me) HP 3310B Function Generator.  I'm starting to see a theme here.

Now read the manuals for all of them and decide what bit you now 'need' to help keep them in Calibration  735A Transfer standard springs to mind 

[bitseeker]

Just got done cleaning up and checking out my new (to me) HP 3310B Function Generator.  I'm starting to see a theme here.

I like where this collection is heading. Mine has three different generations so far: 3310A, 3312A, and 33120A.

[bd139]

Yeah that’s a fine collection 

Still need me a 427A

[Ero-Shan]

Love all those big knobs to fondle.

That's why I would love to have one of them! These are real knobs. They can be fondled even with gloved hands.

[bd139]

Got my PCB for my alarm replacement / SLA charger through and found 18 errors on it on my part 

I suck

Revision 2 in progress...

[tautech]

Got my PCB for my alarm replacement / SLA charger through and found 18 errors on it on my part 

I suck

Revision 2 in progress...

Well the trick is to print the PCB layout on paper and check them first. 

New name: bd139L

[bd139]

I did actually do that but missed a few boo boos. It'll basically work and isn't functionally wrong. It's stuff like the SCR crowbar's ground side terminal is connected by a trace of 0.5mm across (from the ground flood) which is probably going to melt before the fuse does etc etc.

I usually have to do 3 runs before I'm happy and this is the first so not that bothered yet

[ArthurDent]

kj7e -

"I forgot to add, I have an external PCTEL GPS Timing antenna which does a great job..."

I use 2 of the PCTEL antennas with a clear view of the sky as shown below. Each antenna drives a L1 distribution amplifier so I can have multiple GPS receivers running at the same time. One of my receivers that is running 24/7 drives a 10Mhz DA to send 10Mhz to all my other equipment. In the middle of the equipment photo below is a 25-year old Rb standard that is very stable and has 10Mhz buffered outputs plus one 1Ghz output with Rb stability. 

[mnementh]

I did actually do that but missed a few boo boos. It'll basically work and isn't functionally wrong. It's stuff like the SCR crowbar's ground side terminal is connected by a trace of 0.5mm across (from the ground flood) which is probably going to melt before the fuse does etc etc.

I usually have to do 3 runs before I'm happy and this is the first so not that bothered yet

If your crowbar doesn't work, try the "Stick of Wisdom"... 

mnem
*off to do battle with the front lawn... again*

[bd139]

Well the GPSDO arrived and I rather like it.

Comes in a neat little case, well packaged with GPS antenna and USB cable.

Chucked the GPS antenna out of the window, plugged it all in to the PC, connected my counter and downloaded the software and it works. Zero hassle. No drivers required.

Software. Location removed



Yep that counter is out .... 7Hz from factory. Pfft!



Will cal the OCXO and other counters later.

[mnementh]

Try a little percussive maintenance... that ALWAYS works. 

mnem
*agitating-ily*

[med6753]

The Tek 7904 PSU on the bench. The pop and magic smoke originated at the top left corner of the shield. So....let's pull it apart.



Done. Problem found in 30 seconds. And it's a self-inflicted gunshot wound.  Those are two 22uf tants in parallel to replace a 47uf done by me on the pre-regulator board. Obviously I installed one of them backwards. Didn't like it too much.    I don't have a 47uf nor a 22uf in stock. But do have a 15uf/25V. I'll replace it with that cap.



So....apparently the old CRT is indeed bad. The original problem started before I re-capped the pre-regulator. Which is why after installing replacement CRT power came up for short time then this cap blew. Oh well. Such is life. I'll get this repaired and see what happens. (Crossing fingers and toes).   

[FransW]

That is nearly 1 kHz on 1 GHz
Adjustable on the PFM3000?

[bd139]

Done. Problem found in 30 seconds. And it's a self-inflicted gunshot wound.  Those are two 22uf tants in parallel to replace a 47uf done by me on the pre-regulator board. Obviously I installed one of them backwards. Didn't like it too much.    I don't have a 47uf nor a 22uf in stock. But do have a 15uf/25V. I'll replace it with that cap.

Woooooosh! Hahaha 

I've done that a couple of times. The line is + on tants and - on electrolytics. I burned up some expensive ones a few years ago working that one out

Found the Kemet TAJ SMD ones don't explode - they just get hot and desolder themselves 

So....apparently the old CRT is indeed bad. The original problem started before I re-capped the pre-regulator. Which is why after installing replacement CRT power came up for short time then this cap blew. Oh well. Such is life. I'll get this repaired and see what happens. (Crossing fingers and toes).

Cool. Good luck 

That is nearly 1 kHz on 1 GHz
Adjustable on the PFM3000?

Yeah adjusted it down. It's now 0.5Hz out at 10MHz which is fine. I don't expect miracles out of the PFM3000 TBH as it's a trimcap adjuster and a standard non compensated XO. nothing fancy. 2Hz tolerance at 10MHz is fine. My narrowest filter is 200Hz so 1% of that is good enough.

Going to do the HP 5334B later in the week. That has external OCXO reference now.

Plan is to connect the external XO and the GPSDO to two channels on scope and adjust until the traces track, then whack it into the 5334B ext ref and check it.

[med6753]

This Tek 7904 is becoming a real thorn in my side. Got it all back together and have a trace. But no trigger plus vertical issues. Turns out several of the supply voltages.....+/- 15V and 5V are reading way low. Resistance checks show it's in the supply. This makes no sense. All those voltages were fine after I re-capped the pre-regulator board. So I have to pull the PSU again and figure out what happen. This sucks. 

[Specmaster]

Done. Problem found in 30 seconds. And it's a self-inflicted gunshot wound.  Those are two 22uf tants in parallel to replace a 47uf done by me on the pre-regulator board. Obviously I installed one of them backwards. Didn't like it too much.    I don't have a 47uf nor a 22uf in stock. But do have a 15uf/25V. I'll replace it with that cap.

Woooooosh! Hahaha 

I've done that a couple of times. The line is + on tants and - on electrolytics. I burned up some expensive ones a few years ago working that one out

Found the Kemet TAJ SMD ones don't explode - they just get hot and desolder themselves 

So....apparently the old CRT is indeed bad. The original problem started before I re-capped the pre-regulator. Which is why after installing replacement CRT power came up for short time then this cap blew. Oh well. Such is life. I'll get this repaired and see what happens. (Crossing fingers and toes).

Cool. Good luck 

That is nearly 1 kHz on 1 GHz
Adjustable on the PFM3000?

Yeah adjusted it down. It's now 0.5Hz out at 10MHz which is fine. I don't expect miracles out of the PFM3000 TBH as it's a trimcap adjuster and a standard non compensated XO. nothing fancy. 2Hz tolerance at 10MHz is fine. My narrowest filter is 200Hz so 1% of that is good enough.

Going to do the HP 5334B later in the week. That has external OCXO reference now.

Plan is to connect the external XO and the GPSDO to two channels on scope and adjust until the traces track, then whack it into the 5334B ext ref and check it.

Some tants just have a longer leg on the positive, which is a bastard if leg has clipped short for some reason as you then have a 50/50 chance of getting it right  Why cant they all use a common standard of marking that is good across all kinds of polarised caps, oh of stupid old me, that too fecking logical that's why 

[med6753]

Freaking magic. I pulled the PSU. No shorts. No low resistance readings. Pulled all the plug-ins then checked mainframe resistance readings as per manual. No shorts. No low resistance readings. Reconnected PSU one connector at a time and verified no shorts. Left all the plug-ins out and powered up. The -50V, +/-15V, and +5V reading low. The -50V is the reference. Earlier it was reading -53V, now reading -47.5V. It's the one supply voltage that has an adjustment. Set it to -50V. Now the +/-15V and +5V in spec. Inserted plug-ins. Powered up.

She's alive! 



Don't know what happen earlier. Must have been a connector one pin off or something. New CRT looks excellent. Now I gotta get it all back together. The PSU is hanging out the back and other assorted shit draped all over.