Test Equipment Anonymous

Cerebus wrote: ↑Tue Nov 29, 2022 4:54 pm You can never have too many woodworking clamps or too much memory.

Stop spending my money!

by BD

mnementh wrote: ↑Tue Nov 29, 2022 3:29 pm It's a Dell fleet box... first thing I'd check is the PSU

Oh I did not inspected the PSU... on my list.... yes it is an ATX one... but it is mounted on a strange "opening door" construction.

Stupid Zucca I was so excited to see a spotless MB that the PSU zoomed away....

Look closer. Yours is the right age to be one of their early ATX12VO models.

mnem

ah no, 100% I have a long ATX connector with more than 10pins

Back to TEA
My purchases from the last Peaker Pattenson auction finally arrived today. A TTI TS3021S 30V 2A power supply and a Philips 5503 TV pattern generator.
Looked at the power supply first. No obvious issues visually. The bad news is the ouput is pinned at 42V
So as the service manual is available I started with some measurements befemitter ore jumping to the usual suspects. This quickly confirmed it WAS the usual suspects. One of the output transistors was reding 0.77V Collector to Emitter with the Fluke 8060A. Out of circuit the Peak transistor testor said it was a diode network.
Output stage is 3 2N3055H transistors. Two in parallel with emitter resistors driven by a third in a Darlington arrangement.
Note the H suffix. The manual says the output pair must be the H variant. As I didn't have a pair of 2N3055Hs and I don't have confidence in modern production 3055s even from known sellers, I replaced all 3 transistors with MJ15015s. The MJ15015 is a "enhanced" 2N3055 with higher voltage and power rating (twice the voltage, 50% more power) but, importantly, the same dymanic perfomanace so no stability issues. I even had some MJ15015s that at some time in the past I'd measured the gain at high current and marked. So the output pair are gain matched too.
The lack of and poorly applied thermal compound may have led to the transistors demise. Interestingly the black Phier presets on the PCB were suffering from the worst case of "black plastic fuzz" I've ever seen. The red presets were fine. I've seen this on many items made of black thermoplastic. I think it is plasticiser leaching out. Anyway it was cleaned up.
Put it all back togeter and it's working fine

That black plastic fuzz is hard to forget.... congrats Robert, excellent.

Mmmmmhmmmm... juicy.

mnem

Incoming papers:

• Tek 7000 series Sampling Techniques Primer
• Tek TDR For Cable Testing App Note
• Tek ABC's of Probes, vintage unknown
• Tek P6022 Current Probe and Termination Instruction Manual
• Tek TDR Slide Rule nomogram 003-0700-00

for the princely sum of £9.20

25 CPS wrote: ↑Mon Nov 28, 2022 11:45 pm

bitseeker wrote: ↑Mon Nov 28, 2022 3:31 am 25 CPS, that's quite the smorgasbord of nostalgic places, items, and activities to compensate for crummy weather.

It was all over the map and an enjoyable way to spend the weekend.

Today I had a nice breakfast and did a bit of reading, then one of my friends from college who also had a midweek day off and I went for a coffee and walk on the beach so both of us could get outside for a bit. I was going to head downstairs and return to the second HP 427A that's been waiting and check out the DC ranges on that. When I got back, this was waiting hidden behind the side door's screen door:



Looks like that GPSDO has arrived. I'm going to unpack that and take a look at that after dinner. If everything checks out with that, I can do the 10 MHz standardization project I've been wanting to do. I'm thinking dinner, unpack the GPSDO and get that set up and see what it does and start checking over that other 427A while it runs.

Well, now, that seems to be quite the skilled delivery person! At first glance, I thought the package was just neatly placed in the threshold, but hidden between the door and screen door is quite over the top: creativity, spatial acuity, and expenditure of effort to the next level.

A bit better luck with the Philips (actually designed and build by Labgear here in Cambridge) PM 5503 TV test generator. It works perfectly. Even the RF output is OK. Yes I still have a TV with an analogue tuner .
Its one of those "no subsitute" bits of test gear and I've not had one for several years sine someone made me a silly offer for a TeleTest one. I still have a potential need for this as there is still some kit that I have with analogue video that won't be going away in a hurry. For example some high resolution and frame rate thermal imagers.
It sits well with my PM 5110 function generator.

Cerebus wrote: ↑Tue Nov 29, 2022 4:54 pm

Zucca wrote: ↑Tue Nov 29, 2022 2:47 pm Plot twist on the thin client PC.
I found a spotless Dell mini tower XPS 8910 in the dump, sticker says i7...
It does not boot because there is no RAM in it. I just ordered 4x16GB DDR4 just to give it a try.
Then MEMTEST86 it and see what happens.
I tend to say 4x8GB is plenty for my bench PC to use it with a Picoscope, but you know me I can't resist to max out the RAM.

Any further particular stress tests you guys suggest to check a dump PC?

You can never have too many woodworking clamps or too much memory.

Or as it happens, test meters and calculators.

tggzzz wrote: ↑Tue Nov 29, 2022 7:46 pm Incoming papers:

• Tek 7000 series Sampling Techniques Primer
• Tek TDR For Cable Testing App Note
• Tek ABC's of Probes, vintage unknown
• Tek P6022 Current Probe and Termination Instruction Manual
• Tek TDR Slide Rule nomogram 003-0700-00

for the princely sum of £9.20

Paid a few 100 for mine but it at least came with the termination and probe.

Cerebus wrote: ↑Tue Nov 29, 2022 4:54 pm
You can never have too many woodworking clamps or too much memory.

I have about 8 clamps. That is a bit thin.

I have about half a TiB RAM over my machines. That usually suffices, but I'm not a stranger to more.

mansaxel wrote: ↑Tue Nov 29, 2022 8:59 pm

Cerebus wrote: ↑Tue Nov 29, 2022 4:54 pm
You can never have too many woodworking clamps or too much memory.

I have about 8 clamps. That is a bit thin.

I've just inherited some, with jaws from 2cm to 1m.

Gave some to daughter, who looked "why would I want those" puzzled - and was using them within a month

Wifey & kids keep snurching my medium & small spring clamps to put on cereal & chip bags... and then they vanish. I literally go to Horror Fraught every few months to buy more.

mnem

bitseeker wrote: ↑Tue Nov 29, 2022 7:47 pm

25 CPS wrote: ↑Mon Nov 28, 2022 11:45 pm

bitseeker wrote: ↑Mon Nov 28, 2022 3:31 am 25 CPS, that's quite the smorgasbord of nostalgic places, items, and activities to compensate for crummy weather.

It was all over the map and an enjoyable way to spend the weekend.

Today I had a nice breakfast and did a bit of reading, then one of my friends from college who also had a midweek day off and I went for a coffee and walk on the beach so both of us could get outside for a bit. I was going to head downstairs and return to the second HP 427A that's been waiting and check out the DC ranges on that. When I got back, this was waiting hidden behind the side door's screen door:



Looks like that GPSDO has arrived. I'm going to unpack that and take a look at that after dinner. If everything checks out with that, I can do the 10 MHz standardization project I've been wanting to do. I'm thinking dinner, unpack the GPSDO and get that set up and see what it does and start checking over that other 427A while it runs.

Well, now, that seems to be quite the skilled delivery person! At first glance, I thought the package was just neatly placed in the threshold, but hidden between the door and screen door is quite over the top: creativity, spatial acuity, and expenditure of effort to the next level.

This is what the usual Canada Post person does.

The previous owner of my house repurposed the old milk box next to the side door as a mail box so the Canada Post person usually drops the letter mail through the slot into the old milk box and puts the parcel between the screen door and side door if it'll fit there.

On another note, I've got an overnight bench test set up and running now. I've got mixed feelings about the output of my 8903B Audio Analyzer:





The THD+N at 1000 hz at 1 volt (top) and 5 volts (bottom) isn't catastrophically bad but not as good as it could be, I think, so I'm going to let it run overnight and see if or how it changes by lunchtime tomorrow per the suggestions in one of Simon Spier's videos while I work on the other stuff I have going.

I'm going to say that the 8903B is in specification with the reservation that the manual doesn't specify an amplitude for this test though. The numbers I'm getting at 1000 Hz and 1 and 5 volts fall in those limits without the benefit of the 80 kHz low pass filter stripping off the top end going into the analyzer side of the machine.

Still, I've seen better performance from other 8903A/B so...

mnementh wrote: ↑Wed Nov 30, 2022 12:05 am Wifey & kids keep snurching my medium & small spring clamps to put on cereal & chip bags... and then they vanish. I literally go to Horror Fraught every few months to buy more.

Clothes pegs do pretty well for sealing bags of things, such as frozen peas and cereals.

I've found a chap can't have too many welding clamps; C clamps, sheet metal clamps, F clamps, long reach C clamps, Mole grips (Vise grips) - small and large, regular and long nosed, and others.

Audio stuff is like eating chocolate, even if it is not necessary is such a joy...

MED6753 wrote: ↑Mon Nov 28, 2022 3:42 am The next time I think I might have too much TE I'll replay this video again.

https://www.youtube.com/watch?v=Shg7VNoIL_g&t=594s

MED6753 wrote: ↑Tue Nov 29, 2022 12:15 am Must have pictures.

They're coming. I'm upstairs hanging out with the cat for a bit while dinner settles, then I'll be heading back down to the basement.

I saw the same video and I envy the space. Judging from the location of the windows, it looks like that workshop's in a basement like mine except it's large and nicely finished. Mine's smaller and it's a totally rough, unfinished room for the most part the way it was built in 1942. Everyone refers to it as the dungeon. I guess that's a big enough hint that I need to do something about the creature comforts.

Another overnight burn in test is set up.





The GPS disciplined oscillator 10 MHz reference project is under way.

I'll start a thread for that and post more pictures there. In the meantime while I get that set up, enjoy the two I put above.

mnementh wrote: ↑Tue Nov 29, 2022 3:29 pm It's a Dell fleet box... first thing I'd check is the PSU

dere u go (do you hear my Italian accent?)
looks ok.

Crappy fan.... let's see iof it boot first when I get the RAM.

25 CPS wrote: ↑Wed Nov 30, 2022 1:04 am

I'm going to say that the 8903B is in specification with the reservation that the manual doesn't specify an amplitude for this test though. The numbers I'm getting at 1000 Hz and 1 and 5 volts fall in those limits without the benefit of the 80 kHz low pass filter stripping off the top end going into the analyzer side of the machine.

Still, I've seen better performance from other 8903A/B so...

For reference, here's mine; it seems to be pretty close to what yours is displaying.

1 kHz @ 1 V, no 80 kHz low pass filter:


1 kHz @ 1 V, 80 kHz low pass filter in:


1 kHz @ 5 V, no 80 kHz low pass filter:


1 kHz @ 1 V, 80 kHz low pass filter in:


-Pat

Cubdriver wrote: ↑Wed Nov 30, 2022 5:47 am

25 CPS wrote: ↑Wed Nov 30, 2022 1:04 am

I'm going to say that the 8903B is in specification with the reservation that the manual doesn't specify an amplitude for this test though. The numbers I'm getting at 1000 Hz and 1 and 5 volts fall in those limits without the benefit of the 80 kHz low pass filter stripping off the top end going into the analyzer side of the machine.

Still, I've seen better performance from other 8903A/B so...

For reference, here's mine; it seems to be pretty close to what yours is displaying.

1 kHz @ 1 V, no 80 kHz low pass filter:


1 kHz @ 1 V, 80 kHz low pass filter in:


1 kHz @ 5 V, no 80 kHz low pass filter:


1 kHz @ 1 V, 80 kHz low pass filter in:


-Pat

Thanks for posting that - it's reassuring to see some consistency between the performance of the two HP 8903Bs. I was playing around with the 80 kHz filter on mine while I was watching the GPS disciplined oscillator results and I saw a similar reduction in THD+N figures when it's in circuit.

I just finished posting the GPSDO topic and it's got lots of pictures including one showing both burn in tests set up to go overnight. If all goes well, it looks like I'll be stopping in at the local electronics brick and mortar tomorrow to pick up some cables so I can start wiring in 10 MHz reference permanently.

25 CPS wrote: ↑Wed Nov 30, 2022 5:59 am Thanks for posting that - it's reassuring to see some consistency between the performance of the two HP 8903Bs. I was playing around with the 80 kHz filter on mine while I was watching the GPS disciplined oscillator results and I saw a similar reduction in THD+N figures when it's in circuit.

I just finished posting the GPSDO topic and it's got lots of pictures including one showing both burn in tests set up to go overnight. If all goes well, it looks like I'll be stopping in at the local electronics brick and mortar tomorrow to pick up some cables so I can start wiring in 10 MHz reference permanently.

I just saw your GPSDO post. I *still* haven't set up the one I bought years ago - still need to rig an antenna. Probably not gonna be doing it now with the cold weather coming. Those DAs look interesting.

I'll leave my 8903B on overnight to see if anything changes, too, so there will be more data points.

-Pat