My "new" old Schlumberger SI 7063 DMM

[kultakala]

Details on upper board, what are these red square parts ?

[kultakala]

That is under the small add-on board...

And what is that Cerberus SC 1700 ?

[alm]

The red square parts are Coto relays, likely used for switching between ranges and functions. The SC1700 is a sparkgap, to protect against high voltages on the input.

[kultakala]

The red square parts are Coto relays, likely used for switching between ranges and functions.

I thought so, but was not sure, thanks!

[mimmus78]

We all are missing the voltage reference there :-)

Inviato dal mio Nexus 6P utilizzando Tapatalk

[mimmus78]

Maybe d301 near the op77?

Inviato dal mio Nexus 6P utilizzando Tapatalk

[Micke]

I agree!
D301 looks to be a 1N829 (selected for low noise, and thermally cycled to find just the correct current to get close to zero TC) which is commonly used here and there... (for example in most EDC Voltage calibrators)
Nice gold plated Vishay hermetic DIL resistor networks!

[kultakala]

I agree!
D301 looks to be a 1N829 (selected for low noise, and thermally cycled to find just the correct current to get close to zero TC) which is commonly used here and there... (for example in most EDC Voltage calibrators)
Nice gold plated Vishay hermetic DIL resistor networks!

You`re right 




What function can this 6cm long 990k resistor under the "high voltage" sheet have ?




And nice strain relief Never saw that before...

[ManateeMafia]

That looks like the Schaffner power input module that may be prone to sudden failure. I replaced the ones in my Solartron 7081. They are easy to change so I would consider it as a first mod. There are many posts about what happens when they fail.

[Kleinstein]

The upper board on the input side looks like the AC part. So the 990 K resistors would be the upper part of the input divider (990K and 10 K).

[tggzzz]

That looks like the Schaffner power input module that may be prone to sudden failure. I replaced the ones in my Solartron 7081. They are easy to change so I would consider it as a first mod. There are many posts about what happens when they fail.

You wouldn't have a part number or URL, would you? I ought to replace the one in my 7081.

Thanks

[ManateeMafia]

The part number I used is FN372-2-22

DigiKey has them but they are not cheap. DK#  817-1167-ND  ~$30US.

[tggzzz]

Thanks for a fast response; that saved me a lot of time. You are right about the price; that's 1/3 the price of the meter itself

I was going to order it from RS, but they are on backorder so I've made my first Digikey order and will see how it pans out.

[kultakala]

That looks like the Schaffner power input module that may be prone to sudden failure. I replaced the ones in my Solartron 7081. They are easy to change so I would consider it as a first mod. There are many posts about what happens when they fail.

Thanks for the hint!
I will check that...

[kultakala]

I dismounted my power entry module and i need a FN372-2-21, because of the different fuses (European version).

Digikey and RS both have them...  i ordered through RS because the shipment cost is clearly lower.

And mine was made in switzerland so its probaly a risky one.

[tggzzz]

About 10 minutes ago I finished fitting a new FN372-2-22 for my 7081. Since RS didn't have any in stock, I got one from Digikey.

I had to transfer the fuseholders from the old filter to the new one, since the new fuseholders required 30mm fuses and I wanted to reuse the old 20mm fuses.

[kultakala]

About 10 minutes ago I finished fitting a new FN372-2-22 for my 7081. Since RS didn't have any in stock, I got one from Digikey.

I had to transfer the fuseholders from the old filter to the new one, since the new fuseholders required 30mm fuses and I wanted to reuse the old 20mm fuses.

And it works fine ? Good 

I am really impressed by RS. I ordered mine yesterday at 8 pm and today at noon it was here!

The old one has an additional 1 MOhm resistor soldered to the filter (?).
Should i put it onto the new one ?

[tggzzz]

About 10 minutes ago I finished fitting a new FN372-2-22 for my 7081. Since RS didn't have any in stock, I got one from Digikey.

I had to transfer the fuseholders from the old filter to the new one, since the new fuseholders required 30mm fuses and I wanted to reuse the old 20mm fuses.

And it works fine ? Good 

On 240V at least!

I am really impressed by RS. I ordered mine yesterday at 8 pm and today at noon it was here!

RS is pretty good, but they seem to have more "awaiting stock" items than before. It is a toss-up whether I get things delivered to my home or to their trade counter 4 miles away.

Farnell is pretty good too, but they have a minimum order value or you pay postage. CPC has a limited range, but can be significantly cheaper than Farnell.

I placed the Digikey order on Sunday, and it arrived early Wednesday from the US mid-west. That kind of thing still stuns me.

The old one has an additional 1 MOhm resistor soldered to the filter (?).
Should i put it onto the new one ?

I got lazy: I couldn't be bothered to find a new one with appropriate ratings and characteristics. I wasn't going to replace an old carbon film resistor. If there's a better reason than bleeding the charge off the filter capacitors, I'll replace it.

[SeanB]

That is the only reason the resistor is there for, but I would replace it with something high voltage rated, or put 3 330k 0.25W resistors in series instead and heatshrink them.

[kultakala]

So, i could take the old one..  or get a new 1W metal oxide one ?

Its not worth to order just one resistor, dont have any here.

[tggzzz]

So, i could take the old one..  or get a new 1W metal oxide one ?

Its not worth to order just one resistor, dont have any here.

I don't know the state of the old one, so I can't answer that.

As for a new one, read the fine data sheet. Don't forget to allow for transients on the mains, so derate generously..

[xrunner]

I was looking for a vintage bench multimeter for a while and was lucky to find a Schlumberger SI 7063 Multimeter at a used equipment store.
It arrived today and here it is

I just have to say, that is one magnificent looking DMM!

[kultakala]

I don't know the state of the old one, so I can't answer that.

Of course you cant
I will stick to the old one...  looks good and still has 1 MOhm, so...

[kultakala]

I just have to say, that is one magnificent looking DMM!

Thanks, it really is

[2N3055]

Put that old one back in if it hasn't any visible signs of damage. And don't replace it with metal film type, it is carbon type for a reason. Carbon types are noisy, but extremely robust for it's size, and perfect for the this one. If you want to replace it you have to find one specced for high voltage. Don't repair what is not broken. Advice to check and replace old tantalum and alu electrolytics is because they go boom or leak , so sort of preventive maintenance... Resistors need to changed only if damaged..