Test Equipment Anonymous (TEA) group therapy thread

[25 CPS]

Just a quick post.  The Fluke 27 with HV and RF probes arrived last night.  I got a smartphone notification saying delivered while I was fixing some stuff up in the back yard.  Sure enough, it was on the porch when I walked up front.  I’m going to test it out in a little bit.  The insulation tester is going to be the quick and easy power source for testing the two high high voltage probes.

[Vince]

I am weak, look what I just got today !

I saw it a week ago, decided not to buy it as I don't feel attracted to these scopes, and it was defective, and at 50 Euros thought it was not economically viable to try to fix it.

But then ShakalNokturn later out of the blue, pointed me to this scope again... I said no, have already made my mind.

But then I changed my mind... because I am weak, that's all.


- I looked on Ebay and realized these scopes command much higher prices than I thought, even defective ones. So I thought OK maybe I can fix and make a few buck profit, and if not, could still sell it broken and STILL make a bit of profit ! So not much to lose...

- Front panel looked brand new, super clean

- Was an IBM branded one, not a mundane "general consumption" one.

- Even came with some IBM branded paper work, for some memorabilia...

- Came with 3 probes

- Came with the front cover

-.... and also, well mostly, for a change, it was LOCAL to me, literally a 10 minute drive ! 

So I thought, not much to lose...

So, I contacted the guy, offering 40 Euros not 50.. hoping he would tell me to get lost and I would not have to buy it. But, he accepted my offer !
So, 40 Euros for a pristine IBM one, I guess I had not much to lose...  so went to pick it up a couple hours ago.

So here it is... a 453 scope. 2x50MHz + dual time base.

It's missing all 4 feet both at the bottom and at the rear ! I gather it's a common disease on these scopes.. hence why I saw people on Ebay selling 3DP reproductions of these feet....
The blue covers have giant black marker writings on them as you do, and the pain looks tired. So repainting them would not hurt.
Other than than it's brand spanking new inside out.
Everything on the front panel look new. All the BNC and bright work are clean smooth and shiny. All the knobs are  brand new, shiny, and super clean, and when you operate them the feel and sound brand new as well. Inside, pristine too. Not a speck of dust or corrosion or discoloration of the wires insulation or the colour stripes on them. It looks like this scope has ever or rarely been powered up...

The construction of it is luxurious. Old gold plated PCB, sockets for all the trannies. The cabinet is made of thick cast aluminium plates front and back, and matching side beams. Inside, the usual fold aluminium sheet chassis.
Linear power supply, big transformer in the thing.
all in all explains why this compact scope weighs so much !! 

The 3 probes are all Tek :

x10 P6054A
x10 P6010
x1  P6011

Also came with a plastic bag full of little accessories. Have the 3 ground leads but they look useless : they are terminated not with the usual alligator clip, but instead with a thread ! Some of the accessories look like they are meant to screw on these threads but, and that they are meant to plug onto male pins/test points... weird.

Came with a couple BNC- single binding post adapters. Like new. Guess I can make use of these.

Anyway I am fucked now : I didn't like these scopes before, but now I have a brand new one on my bench, in the flesh, that I see how nice it is, I can't get myself to sell it ! Even for a profit.
Luckily cost me only 40 Euros and zero shipping  so it's not a huge expense.

As for fixing it, not sure it can be fixed, but I will keep it anyway....

Guy said he knew nothing about scopes, a 70+ yo chap, said he got it from his mother in law (which therefore must have witnessed the construction of the Titanic ! ). Said he powered it up, he saw a trace on the screen, then after 30 minutes or something the trace disappeared.

I tested the scope, you can get a trace no matter whzat you do. I guess the CRT HV transformer just gave up the ghost, probably, and good luck finding another one of those, never mind at a price that makes sense.  Will try and probe around a little just in case I get lucky and it's some discrete component instead, but I am not too hopeful !    Will only do it for the fun of working on it, but zero hope as far as I am concerned.... 

[Vince]

Eh ?! Since when does Dwagon have an interest in ancient glowing Tek scopes ?!    Had not gathered that so far ?! 

And... I thought another GWN fellow the other day talked about getting it ! You stole it from him ? Not nice !

No, I think this is a little coöperation between TE people. All will be well.

Ah OK cool, I prefer that. I was this close from swimming across the Atlantic ocean to go get the Dwagon and cut his tail off.

[dl6lr]

Good to see you are using proper Meissen-lation techniques!   

isolain porcelation...

[tggzzz]

So here it is... a 453 scope.
The 3 probes are all Tek :
x10 P6054A
x10 P6010
x1  P6011
Also came with a plastic bag full of little accessories. Have the 3 ground leads but they look useless : they are terminated not with the usual alligator clip, but instead with a thread !

Good find!

The alligator clips screw onto those threads.

[med6753]

So here it is... a 453 scope.
The 3 probes are all Tek :
x10 P6054A
x10 P6010
x1  P6011
Also came with a plastic bag full of little accessories. Have the 3 ground leads but they look useless : they are terminated not with the usual alligator clip, but instead with a thread !

Good find!

The alligator clips screw onto those threads.

That's an original IBM purchase to service S/360 mainframes. In fact, IBM asked Tek to design it specifically for that purpose and be portable so it could be easily brought to a customer's office and could be carried aboard flights. 

[med6753]

Guy said he knew nothing about scopes, a 70+ yo chap, said he got it from his mother in law (which therefore must have witnessed the construction of the Titanic ! ). Said he powered it up, he saw a trace on the screen, then after 30 minutes or something the trace disappeared.

I tested the scope, you can get a trace no matter whzat you do. I guess the CRT HV transformer just gave up the ghost, probably, and good luck finding another one of those, never mind at a price that makes sense.  Will try and probe around a little just in case I get lucky and it's some discrete component instead, but I am not too hopeful !    Will only do it for the fun of working on it, but zero hope as far as I am concerned.... 

Rule number 1, Rule number 2, Rule number 100. Power Supply, power supply, power supply. Test it first. All voltages must be present. It's not a difficult scope to work on. It's nearly identical to my 454.

[med6753]

It is in my trunk. Looks like exactly as described. In fact, I think this was the fellow I bought that HP 54645A training signal board from a year or so ago. 

mnem
*on my way home*

If you want to stay in my good graces you must post pix of the internals of that Type 564. 

[Vince]

So here it is... a 453 scope.
The 3 probes are all Tek :
x10 P6054A
x10 P6010
x1  P6011
Also came with a plastic bag full of little accessories. Have the 3 ground leads but they look useless : they are terminated not with the usual alligator clip, but instead with a thread !

Good find!

The alligator clips screw onto those threads.

Yeah that's what I was hoping too  ! Alas no luck ! These alligator clips look like they are meant to fit a banana plug ! Except tehy are too small to fit on a standard 4mm plug, and too big to fit on a 2mm one. I am a bit at a loss here, confused 

[Vince]

So here it is... a 453 scope.

That's an original IBM purchase to service S/360 mainframes. In fact, IBM asked Tek to design it specifically for that purpose and be portable so it could be easily brought to a customer's office and could be carried aboard flights.

Yeah I remember reading about this, hence why I immediately noticed it was branded IBM on the face plate and thought it was cool and added bit of historical value to it 

As for voltages yeah but I don't find obvious test points for them. Am trying to download the manual from Tekwiki but the download keeps failing ! Driving me nuts. So in the meantime I am doing it impro style, just looking around.

I noticed on a small board atop the main transformer, a dodgy looking axial electrolytic cap. Some nasty looking substance escaped from it, see picture...
I pulled it and measured it. Somehow capacitance and even ESR were still fine ! I replaced it anyway just to see if it would make any difference at all.
It's a 3uF 150V one. Plenty of 3,3uF but all low voltage. Closed I had with a high voltage rating was a 4,7uF 150V. Good enough for testing purposes I thought. So I soldered that in. Made no difference. Oh well...

Then I flipped that board, and underneath I found a sub-chassis holding a couple TO-3 upside down. I noticed something weird around their base/emitter pins, see pic. Lots of foreign material so to speak... looks like small seeds or cooked insect eggs or something, weird. I though hey maybe these trannies are HV stuff to do with the CRT. At HV those eggs might lead to a leak and disturb the circuitry why not... so I removed all the nasty stuff. Then quick sanity check of these two trannies. Did a diode test between the two pins, base and emitter then. Read 100mV both ways, on both trannies, not good. So I pulled one of the wires on both trannies to take them out of circuit so I could get a reliable reading. They then tested both just fine. So soldered the wires back in.

Powered up the scope.. still no improvement or change, nada.

So then since I highly suspected the lack of CRT HV, I went straight to that as it's easy enough to test without a manual...
Flipped the scope on its side, popped the bottom cover, then popped the HV danger shield, then underneath it yet another shield, transparent plastic this time, popped that one too. Now I had the guts of the HV CRT stuff all exposed to me.
dug out my HV probe, measured the cathode voltage, should be negative 1950V according to the printing on the shield. Measured 0.000.....
the probed the positive anode voltage, should get several kV. Got 0.000 again !
OK so I was right, we lack CRT HV, both the cathode and anode.
Quick visual check of all the components in there... nothing blatantly wrong.

So since I am missing both cathode and anode HV, and since both are at completely dead, 0.00... this means I guess it must be either a bad transformer or a the oscillator driving its primary is dead. So need to check for that... but need the manual to look at the schematic and see where the oscillator is located.

So at this point there is still a slight chance that the transformer is OK and that it's only some discrete component in the oscillator that failed. Crossing fingers...

Now if I could bloody manage to download this freaking service manual !!!!! 

[med6753]

Round 2 of the mini 212 restoration. Bring up the PSU with no load. To make things safe to work on substituted the hp 6215A power supply for the AC mains connection. Set it to 13.5V and placed it across the batteries. It will also allow me to monitor the current. The HV for the CRT (1kV) is also on that board. I disabled it for now by pulling 2 HV diodes.

The result? We have life! The PSU comes up. The +5.6V is measuring over +6.5V because of no load. The +69V also present but high due to no load. I was worried that the inverter transformer might be shorted so that's a big relief. 

Next step is check the main board for shorts and connect it. The tants for this project should arrive tomorrow.

[med6753]

Vince, that board with the dodgy capacitor is the PSU regulator board. As soon as you can get the manual to download it will give you the PSU voltage test points. Don't assume the HV itself is the issue until AFTER verifying all the PSU voltages. 

[xrunner]

Wow - so far a whole page related to TEA. I don't know what to think ... 

[med6753]

Wow - so far a whole page related to TEA. I don't know what to think ... 

Shhhhh.....Don't jinx it. 

[mansaxel]

TE usage today:

Fluke 10 at my parents place, replacing a ceiling lamp. There were a pair of wires, white and blue insulation, coming out of a strangely small flexible conduit which in turn emanated from a hole in the ceiling tile. Made a hole for and fitted the expander hook, measured voltage on the wire pair, made certain it was off, and installed.  Not very advanced, but still, life improved by owning TE.

Annoying issue: I need to refill my bootlace ferrule stash in the tool bag. Have run out.

[factory]

Why are the dial covers always missing on 735As ?

Not all of them have the plastic dial, below S/N 00737 have a different dial with an extra lamp fitted too.


David

[mnementh]

It is in my trunk. Looks like exactly as described. In fact, I think this was the fellow I bought that HP 54645A training signal board from a year or so ago. 

mnem
*on my way home*

If you want to stay in my good graces you must post pix of the internals of that Type 564. 

Not sure how well Al would take it if I were to undress his new girl and post pictures on the intar-webbzz...     

OTOH... What's it worth tooya...?

mnem
"Hey, hey mister... got any nekkid pictures of your wife...?"
"Well I never... Of course not!"
"Wanna buy some...?"

[mnementh]

I am weak, look what I just got today !

I saw it a week ago, decided not to buy it as I don't feel attracted to these scopes, and it was defective, and at 50 Euros thought it was not economically viable to try to fix it.

But then ShakalNokturn later out of the blue, pointed me to this scope again... I said no, have already made my mind.

But then I changed my mind... because I am weak, that's all...

mnem
"No thanks..." is what I should have said...

[factory]

So here it is... a 453 scope.

That's an original IBM purchase to service S/360 mainframes. In fact, IBM asked Tek to design it specifically for that purpose and be portable so it could be easily brought to a customer's office and could be carried aboard flights.

Yeah I remember reading about this, hence why I immediately noticed it was branded IBM on the face plate and thought it was cool and added bit of historical value to it 

As for voltages yeah but I don't find obvious test points for them. Am trying to download the manual from Tekwiki but the download keeps failing ! Driving me nuts. So in the meantime I am doing it impro style, just looking around.

I noticed on a small board atop the main transformer, a dodgy looking axial electrolytic cap. Some nasty looking substance escaped from it, see picture...
I pulled it and measured it. Somehow capacitance and even ESR were still fine ! I replaced it anyway just to see if it would make any difference at all.
It's a 3uF 150V one. Plenty of 3,3uF but all low voltage. Closed I had with a high voltage rating was a 4,7uF 150V. Good enough for testing purposes I thought. So I soldered that in. Made no difference. Oh well...


......snip......

Now if I could bloody manage to download this freaking service manual !!!!! 

That capacitor is a Sprague 109D wet tant  they are well known for leaking the acidic electrolyte, following failure of the seal.

The first 453 manual on Tek-wiki is 143MB, could your web connection be timing out? The military manual is only around 8MB, maybe that will work.  The one labelled OCR don't work for me, just goes to a log-in page.
 
David

[Cubdriver]

So since I am missing both cathode and anode HV, and since both are at completely dead, 0.00... this means I guess it must be either a bad transformer or a the oscillator driving its primary is dead. So need to check for that... but need the manual to look at the schematic and see where the oscillator is located.

So at this point there is still a slight chance that the transformer is OK and that it's only some discrete component in the oscillator that failed. Crossing fingers...

Now if I could bloody manage to download this freaking service manual !!!!! 

...or it could be an issue with the main power supply.  That axial cap you posted a photo of looks rather unhealthy.  If the main power supply is not working, it will cause the oscillator and other dependent stuff not to work either.  If the car won't start, make sure there's gas in the tank before pulling the engine to check the main bearings.  I generally live by the axiom that an optimist is frequently disappointed whereas a pessimist is often pleasantly surprised, but start with the basics before jumping to the worst case scenario, Vince!

-Pat

[25 CPS]

Slow day so I decided to go ahead and test the Fluke 27.  No go.  I checked the 9 V Eveready battery that was included before installing it and it measured 8.6 V so I put it in figuring it’s close enough to get me through some quick testing and the meter didn’t start up up.



Take the battery door off the Fluke again and measure the battery with the function knob turned back to the off position and it’s collapsed to 5.9 V.





Turn the Fluke back on to DC Volts and it pulls that 9 V Eveready all the way down to 3.08 Volts.  Putting it in the Fluke and trying to use it completely killed it.  It never recovered to the 8.6 V I measured it at before using it.  This probably going to have to wait until tomorrow evening and buying a fresh 9 V battery since I’m visiting my parents tonight.

[Vince]

So here it is... a 453 scope.

That's an original IBM purchase to service S/360 mainframes. In fact, IBM asked Tek to design it specifically for that purpose and be portable so it could be easily brought to a customer's office and could be carried aboard flights.

Yeah I remember reading about this, hence why I immediately noticed it was branded IBM on the face plate and thought it was cool and added bit of historical value to it 

As for voltages yeah but I don't find obvious test points for them. Am trying to download the manual from Tekwiki but the download keeps failing ! Driving me nuts. So in the meantime I am doing it impro style, just looking around.

I noticed on a small board atop the main transformer, a dodgy looking axial electrolytic cap. Some nasty looking substance escaped from it, see picture...
I pulled it and measured it. Somehow capacitance and even ESR were still fine ! I replaced it anyway just to see if it would make any difference at all.
It's a 3uF 150V one. Plenty of 3,3uF but all low voltage. Closed I had with a high voltage rating was a 4,7uF 150V. Good enough for testing purposes I thought. So I soldered that in. Made no difference. Oh well...


......snip......

Now if I could bloody manage to download this freaking service manual !!!!! 

That capacitor is a Sprague 109D wet tant  they are well known for leaking the acidic electrolyte, following failure of the seal.

Oh, those again ?! 

I remember you telling me about these things, when I showed the two crusty one in the trigger rotactor in my HP 120B scope !

The first 453 manual on Tek-wiki is 143MB, could your web connection be timing out? The military manual is only around 8MB, maybe that will work.  The one labelled OCR don't work for me, just goes to a log-in page.

Crappy 4G modem here... but finally managed to download that 143MB beast of a service manual !!!  I have something to work with now!

Checked voltages on the power board.

150V UNREG : 160V, good enough. Ripple 250mV AVG, good enough for a highish voltage unreg.
+75V : 75V next to zero ripple
-12V : -12V next to zero ripple
+12V : 10,65V next to zero ripple NOT happy...

So the +12V is low. Trimmer was set halfway. If I play with it I can make that rail between 9,75V and 11,5V not more. If I disconnect the output wire to isolate the supply/unload it, it climbs at 20V or so. So it can produce the voltage, just not maintain it. So either a tired pass transistors, or I guess more likely the scope is overloading the supply thanks to a tired electrolytic cap somewhere... good luck finding it. Will take ohms measurements, maybe the manual gives some values I can compare with.

Still, I doubt this low +12V rail is causing the issue... I mean I can set it to 11,5V which is not that far off let's be real. It should not cause havoc to the point of keeping the scope from displaying anything on the screen...
I guess I can quickly hook an external 12V supply to confirm that. It would also let me witness how much current this rail is drawing, it can only be interesting. OK let's do that then...

But I am extremely doubtful this 12V rail is the main culprit here, because according to the schematics of the CRT circuit... the oscillator that drives the HT transformer, runs off of the 75V rail, and this rail is fine. The primary of the HV transformer is fed with 16V or so, unreg, tapped from the diode bridge / main filter cap of the +12V supply. That rails works too. A liittle weak, but it's there.

So now the next step I think is to locate the CRT board so I can probe directly in there to make sure the 75V and 16V are indeed getting there. Problem is that I can't find this board !     Must be hiding somewhere inside the scope, underneath another board or what not. Hoping it can be accessed without dismantling the scope to the point where it can't be powered any more... would suck.  Need to check the manual to locate that board....

Anyway, making progress... I think !

[25 CPS]

9812 on the bottom.  Is this a date code?  It’s the only thing on the battery that looks like one so December, 1998 maybe?





In any event, those nine lives are gone.  Even my black cat’s more energetic than Eveready’s black cat.

[mansaxel]

Slow day so I decided to go ahead and test the Fluke 27.  No go.  I checked the 9 V Eveready battery that was included before installing it and it measured 8.6 V so I put it in figuring it’s close enough to get me through some quick testing and the meter didn’t start up up.

<snip>

 Putting it in the Fluke and trying to use it completely killed it. 

Did you get a service manual? If so, the fairness algorithm is at least trying  because the battery that I got with my 27 works.  Was yours calibrated and stickerized?

[Vince]

So since I am missing both cathode and anode HV, and since both are at completely dead, 0.00... this means I guess it must be either a bad transformer or a the oscillator driving its primary is dead. So need to check for that... but need the manual to look at the schematic and see where the oscillator is located.

So at this point there is still a slight chance that the transformer is OK and that it's only some discrete component in the oscillator that failed. Crossing fingers...

Now if I could bloody manage to download this freaking service manual !!!!! 

...or it could be an issue with the main power supply.  That axial cap you posted a photo of looks rather unhealthy.  If the main power supply is not working, it will cause the oscillator and other dependent stuff not to work either.  If the car won't start, make sure there's gas in the tank before pulling the engine to check the main bearings.  I generally live by the axiom that an optimist is frequently disappointed whereas a pessimist is often pleasantly surprised, but start with the basics before jumping to the worst case scenario, Vince!

-Pat

Oops you posted while I was composing my previous message.. you will find some answers there ! 

As for that crusty tantalum, I forgot to say that I looked it up in the schematic (see attached). It's C1194, 3uF.  Don't know what it does exactly as I am not very smart and didn't design  the thing, but it's part of the regulation circuitry, between the reference voltage and feedback path. It's part of the 75V supply... and this rail works just fine, it's spot on. So clearly even with my 4,7uF replacement cap, it still works fine...
Will replace it with a new ca of the correct value later of course, if / when I manage to fix the scope. But for now it will do just fine !