Test Equipment Anonymous (TEA) group therapy thread

[factory]

Greetings: Mr Factory/ BatGS:
   Confirming this unit you speak of and included the great images is a THM-565?
   I recently acquired the Mac ET-2020 version you spoke. The shop mechanic told me it functioned then quit after he found the batteries corroded. He cleaned the holder and it still did not function... No surprise there. We know what happened. He said it was buried in the shop many years untill he was cleaning up, which is when it was offered to me... "cheap" so he said. Me, being an electronics tech and service trucks, autos, marine, Etc .. it caught my eye. No time for research, figuring it a simple repair I dropped him from $500 down to $300. Stupid me impulse buy. Well, maybe not all stupid. I have a nice $300 case full of accessories and a tough looking paperweight.
   Now my premise - I read your entries and viewed images. The PCBAs seem to match as do the parts so few I checked. Prior this site I diagnosed it a power supply issue.Your idea of the caps I'm was part of my repair idea. I am concerned of the replacement 1174 regulators. The little information I found has different part #s as replacement. I prefer a DIP as I hate SMD stuff. I have various data sheets on the 1174 however there is so many versions. Did you replace the regulators? If yes, which part #s and source (reference). I realize your 1174 # will vary a little because of the DIP package I choose. I saw it allows Eml from members here. U can just make sure U have EEVBLOG + your username / BatGS in the subject line as protocol proof not spam. If other members have suggestions Follow same Subject line protocol. Thx. BatGS. Mac ET-2020 / THM565.

Yes apart from the firmware, accessories & case markings, they are the same hardware.

No I didn't replace the regulator ICs, because I bodged in some through new hole capacitors (temporary only) to verify if they were OK, which they were, I didn't want to spend $10 per IC (probably more now) if they weren't needed.
I was lucky, the poor connection from the battery corrosion prevented it powering up & frying the regulators, this happens when the surface mount electrolytic capacitors pee conductive electrolyte all over the board.

Make sure they are the correct part, the regulator numbers vary because they are made with different fixed output voltages, you really don't want to order the wrong one, the adjustable output one is the correct part.
Not sure any through hole parts are going to fit in the space, as I regularly say on here, if your not used to working on anything, practice on something similar which has little or no value, before working on this scope.

https://www.mouser.co.uk/datasheet/3/1014/1/1174fe.pdf

David

[factory]

What about the power consumption of these linear lab power supplies?

Here's a quick test to compare the TTi PL330 QMD with a Siglent SPD 3303X-E, both 30V 3A max per channel.

Output V	Output A	Output W	Input W TTI	Input W Siglent
0 V	0 A	0 W	20 W	11 W
1 V	0.1 A	0.1 W	25 W	14 W
10 V	1 A	10 W	71 W	41 W
20 V	2 A	40 W	120 W	86 W
30 V	3 A	90 W	173 W	151 W

What about other differences? ie. fan noise, RF noise, terminal spacing, availability of service data, etc....

David

[factory]

Picked up this Yokogawa 2501 DVM yesterday, found it by accident on feeBay and I wasn't even searching Germany for Yokogawa, it took 5 days to get to Stoke Parcelforce depot and 6 days for Royal Fail Nantwich delivery office to deliver the fee to pay card. 

It's survived the trip OK-ish, one of the handles was trying to make a bid for freedom, along with the matching piece at the back, the difference here is the damage is easier to fix (than HP), just a bit of straightening required to the steel frame and some new screws.

David

[Robert763]

What about the power consumption of these linear lab power supplies?

Here's a quick test to compare the TTi PL330 QMD with a Siglent SPD 3303X-E, both 30V 3A max per channel.

How does the power factor of the two supplies compare? I.e input VA compared to input W? Output V Output A Output W Input W TTI Input W Siglent 0 V 0 A 0 W 20 W 11 W 1 V 0.1 A 0.1 W 25 W 14 W 10 V 1 A 10 W 71 W 41 W 20 V 2 A 40 W 120 W 86 W 30 V 3 A 90 W 173 W 151 W

[/td][/tr][/table]

[2N3055]

Ohh... it sports a 2N3055 ❤️

Sinisa gets around. 

And has for many decades. 
He looks much younger in real life. 

You cannot go wrong: big, slow, strong and reliable.
 

[Peter_O]

snip:
What about the power consumption ...
Here's a quick test ...

What about other differences? ie. fan noise, RF noise, terminal spacing, availability of service data, etc....

Sorry, just a quick test of power consumption. 

Regarding the other criteria: There was a reason to buy the TTi owning the Siglent already.  Beside TEA desease. 

[m k]

Low power Siglent is less than 60% of TTi, but high power is close to 90%.
Maybe old one is just not so EPA certified.

[tautech]

Low power Siglent is less than 60% of TTi, but high power is close to 90%.
Maybe old one is just not so EPA certified.

At higher loads the Siglent's smart fan kicks in so that will add to the power drawn vs zero and low loads when the fan is near silent.

[AVGresponding]

Also the TTi is fully linear, and the Siglent is a switching pre-reg, afaik, so it'll be a lot more efficient

[tautech]

Also the TTi is fully linear, and the Siglent is a switching pre-reg, afaik, so it'll be a lot more efficient

No all SPD models are totally linear PSU's.

The SPS5k and 6k are switchers but none of the SPD PSU models are.

[m k]

(Robert was too sophisticated)

So lower power settings are using newer LDOs, but higher part is closer to what have been.

[Robert763]

(Robert was too sophisticated)

So lower power settings are using newer LDOs, but higher part is closer to what have been.

I suspect that the Siglent linear PSUs are switching the transformer secondary for the lower voltage ranges to reduce dissipation.

robert.

[tautech]

(Robert was too sophisticated)

So lower power settings are using newer LDOs, but higher part is closer to what have been.

I suspect that the Siglent linear PSUs are switching the transformer secondary for the lower voltage ranges to reduce dissipation.

robert.

Wrong again.
They use a # of transformer taps to reduce regulation losses.

[Robert763]

(Robert was too sophisticated)

So lower power settings are using newer LDOs, but higher part is closer to what have been.

I suspect that the Siglent linear PSUs are switching the transformer secondary for the lower voltage ranges to reduce dissipation.

robert.

Wrong again.
They use a # of transformer taps to reduce regulation losses.

That's what I said  and when was I wrong before?

[factory]

(Robert was too sophisticated)

So lower power settings are using newer LDOs, but higher part is closer to what have been.

I suspect that the Siglent linear PSUs are switching the transformer secondary for the lower voltage ranges to reduce dissipation.

robert.

Wrong again.
They use a # of transformer taps to reduce regulation losses.

Then what are the relays for? If they don't switch between parts of the secondary winding?



And what the hell is a smart shart fan? Can't they describe things properly, such as software controlled based on power/temperature, or just temperature controlled? Having said that, things would probably be better kept cool, with it running full speed all the time, based on the above picture. 

David

[tautech]

Having said that, things would probably be better kept cool, with it running full speed all the time, based on the above picture. 

David

That image shows a manufacturing defect where the cap was installed reverse polarity.

No worse than Tek PCB silkscreen errors. 

[factory]

The difference is Tek (before the offshoring) would have probably noticed it blowing up on test & fixed it, whereas the other one they didn't care, just ship it to the customer and forget the warranty, let them fix it themselves, as it's too much hassle to ship internationally.

And what about the two questions you've cut from my post?

David

[tautech]

.........

Then what are the relays for? If they don't switch between parts of the secondary winding?



And what the hell is a smart shart fan? Can't they describe things properly, such as software controlled based on power/temperature, or just temperature controlled? Having said that, things would probably be better kept cool, with it running full speed all the time, based on the above picture. 

David

And what about the two questions you've cut from my post?

Yup the big relays pictured switch the secondary windings.
See the blob of white silicone on the rear edge of the heatsink, under it is a PCB mounted thermistor and there is one on each heatsink of the 2 fully regulated channels in these PSU's.

[Robert763]

.........

Then what are the relays for? If they don't switch between parts of the secondary winding?



And what the hell is a smart shart fan? Can't they describe things properly, such as software controlled based on power/temperature, or just temperature controlled? Having said that, things would probably be better kept cool, with it running full speed all the time, based on the above picture. 

David

And what about the two questions you've cut from my post?

Yup the big relays pictured switch the secondary windings.
See the blob of white silicone on the rear edge of the heatsink, under it is a PCB mounted thermistor and there is one on each heatsink of the 2 fully regulated channels in these PSU's.

@Tautech

So I'll ask again, Where was I "wrong again" and originally?
As a reminder I said:
"I suspect that the Siglent linear PSUs are switching the transformer secondary for the lower voltage ranges to reduce dissipation."

Maybe the "again" was conflation with AVGresponding's comment on switcing pre-regulation, but my statement stands. I don't mind being corrected, but only when I'm wrong.

Robert.

[tautech]

@Tautech

So I'll ask again, Where was I "wrong again" and originally?
As a reminder I said:
"I suspect that the Siglent linear PSUs are switching the transformer secondary for the lower voltage ranges to reduce dissipation."

Maybe the "again" was conflation with AVGresponding's comment on switcing pre-regulation, but my statement stands. I don't mind being corrected, but only when I'm wrong.

Robert.

The word switching got me 1st thing in the morning Robert before the fog wore off, sorry. 

Yes you are correct, the relays switch between the taps, IIRC there are 3 taps for each of the 2 fully regulated channels in the SPD3303X/X-E models.

[Gertjan]

Racal-Dana 1990 universal counter

I really like the Racal-Dana 1999x counters, with their big red displays and 1mHz resolution @ 10MHz. The Racal-Dana 1992 and 1998 are my daily drivers.

So when I saw baby brother Racal-Dana 1990 at a radio rally, I bought it. I told myself I had to buy it for spare parts for the 1992 & 1998. But off course I repaired and polished it.


IMG_4573__Racal-Dana_1990_front-2000pix.jpg

The seller told me that he tested the counters OK, but later on a very hot day he found some not working.
Yea, seller stories....  The input resistor was burned to a crisp:


IMG_4530__Racal-Dana_1990_R1_defect-2000pix.jpg

After replacing this (R1), and one other resistor in series with the input (R14), the counter was operational again, and measured fully in spec. Surviving a big input overload like this without any active parts damaged, is a big compliment to the excellent Racal-Dana input protection!

This entry-level model of the 199x series does not use the Racal TEC technology. This enhanced recipromatic Time Error Correction Technique provides an effective clock frequency of 1GHz to give a single shot time interval measurement resolution of 1ns.
The TEC counters (=rest of the 199x series) are doing 9 digits/sec, and 1ns resolution, the 1990 does 7 digits/sec and 100ns resolution.

Yet the 1990 uses exactly the same custom IC's as it's bigger brothers:


IMG_4553__Racal-Dana_1990_-_main_PCB_component_side-2000pix.jpg

While checking specifications after the input repair I noticed that the minus sign of the exponent display was hardly working. A bit of measuring told me that the multiplexed source was OK, it was the LED itself that had aged.
This LED proved to be an uniquely modelled LED:


IMG_4538__Racal-Dana_1990_min_LEDje-2000pix.jpg

Of course I did not have such a LED in my part bins. So I decided to create one myself.
Original LED with some DIY replacements:


IMG_4541__Minus_LED,_original,_new_and_failed-2000pix.jpg

From left to right: original LED, replacement LED, and a failed replacement. That failed replacement LED shows the difficulty: The LED internal wire-frame is at right-angle with the minus-sign. File a bit too far and you'll hit metal, and the LED is broken.

New minus LED in place:


IMG_4542__Racal-Dana_1990_-_New_minus_LED-2000pix.jpg

And the display with new minus LED:


IMG_4544__Racal-Dana_1990_-_display_with_new_minus_LED-2000pix.jpg

With the new minus LED in place, this Racal-Dana 1990 was ready for use again. And even with less resolution this 1990 proves to be very usable.

It has functions no other 199x counter has: Time measurement, Total A, Delay and Averaging functions.
Trigger level settings are still the same after switching off & on again, and can be measured on the front panel.
It's 9444 OCXO is warm & stable in 8...10 minutes. In contrast to the 9462 Ultra Stability OCXO's in the 1992 and 1998, which are taking hours to stabilise. (For that reason I use the 1992 & 1998 almost exclusively with an external 10MHz reference)

The Racal-Dana 1990 repaired, and standing on the shoulders of it's bigger brothers:


IMG_4582__Racal-Dana_family_1990_1992_1998-2000pix.jpg

regards, Gertjan.

[AVGresponding]

(Robert was too sophisticated)

So lower power settings are using newer LDOs, but higher part is closer to what have been.

I suspect that the Siglent linear PSUs are switching the transformer secondary for the lower voltage ranges to reduce dissipation.

robert.

Yep, you can hear the relay click. The TTi doesn't, so the poor thing has to dump a lot of heat at low voltages, hence they are prone to crispy-board syndrome

[AVGresponding]

@Tautech

So I'll ask again, Where was I "wrong again" and originally?
As a reminder I said:
"I suspect that the Siglent linear PSUs are switching the transformer secondary for the lower voltage ranges to reduce dissipation."

Maybe the "again" was conflation with AVGresponding's comment on switcing pre-regulation, but my statement stands. I don't mind being corrected, but only when I'm wrong.

Robert.

The word switching got me 1st thing in the morning Robert before the fog wore off, sorry. 

Yes you are correct, the relays switch between the taps, IIRC there are 3 taps for each of the 2 fully regulated channels in the SPD3303X/X-E models.

Seems to be 4; 0-8, 8-16, 16-24, and 24-32. There's some hysteresis as well obvs

[AVGresponding]

IMG_4541__Minus_LED,_original,_new_and_failed-2000pix.jpg

From left to right: original LED, replacement LED, and a failed replacement. That failed replacement LED shows the difficulty: The LED internal wire-frame is at right-angle with the minus-sign. File a bit too far and you'll hit metal, and the LED is broken.

regards, Gertjan.

Given that audiophools destroy old TE for the tubes, I think it would have been karmically right if you had destroyed an old piece of audio gear for the little rectangle LEDs in the VU meters...

[Gertjan]

From left to right: original LED, replacement LED, and a failed replacement. That failed replacement LED shows the difficulty: The LED internal wire-frame is at right-angle with the minus-sign. File a bit too far and you'll hit metal, and the LED is broken.

Given that audiophools destroy old TE for the tubes, I think it would have been karmically right if you had destroyed an old piece of audio gear for the little rectangle LEDs in the VU meters...

Unfortunately the orientation of those LED's is wrong. The minus sign would be vertical....


IMG_4675__LED_orientation-2000pix.jpg

regards, Gertjan.