VTVM tune up

[tubesornothing]

OK, so I ought a VTVM - why? Don't ask, it an ebay addiction thing.

Anyways it is a B&K 175 in quite good shape.  Works OK.  Any suggestions for a tune up?  Or the typical clean the pots and replace the elec caps...

[FYL]

A typical tune-up will be OK, plus some anti-static spray on the bezel.

[jhadhar65]

Is there a measurement testing standard to go by with these?  I figure 'typical tune-up' means check all resistors and caps, replace tubes and electos (?), but what can you do to make sure it's working properly and/or properly adjusted?

[jjasilli]

These puppies need to be calibrated.  But you can check its reading against a known good meter.  

It also helps to have a 1M probe.  You can probably find a manual on eBay or google it on the net.  

I've bought similar items on eBay.  It might cost a bit more but I've learned (the hard way) to hold out for an item from a hi-rated seller, guaranteed to be in proper working condition, preferably calibrated, and with all probes and manuals.  

[jhadhar65]

Who can calibrate it or is this something we can do ourselves?

EDIT:  I'm eyeballing an HP410B on stinkBay that's not guaranteed to work and probably doesn't.  If it's no harder to get working than it is to build amps, I'd like to try for it.  I've just never had my hands on one and I don't know.

[jjasilli]

Yes you can calibrate the old VTVM's yourself.  I bought an old Heathkit IM-18 for about $10.  The probe came broken; the battery holder inside was corroded; and the darn thing didn't work anyway, though it was supposed to. No manual.  But I got it real cheap and even shipping was covered, 'cause I bought another item from the same seller at the same time.  The seller was real nice and offered to take it back for a refund.  But I kept it.  And it has 2 Mullard tubes in it, one a 12au7!

So I bought an identical unit, guaranteed to work, from another seller with a manual, probes, etc.  It works great, though I had to calibrate it.  The manual tells how.  With the manual I should be able to fix the first purchased unit; but I'd rather work on amps!

So, bottom line: you're taking on a new skill set to use this old equipment.  It's a way to possibly get some really neat tubes and trannies.  

But if the unit doesn't come complete, it's a whole new hobby taking time and money to acquire & refurbish the equipment, find manuals, and probes, etc., etc.

Still I went through a phase and got an old tube signal tracer (listening amp), sencore mighty mite tube tester, a signal generator, a resistor-capacitor comparitor with the eye-tube!, and a few resistance-capacitance decade boxes.  All were guaranteed to work and came with manuals and probes for applicable items.  Even so I had to do an easy fix to the comparitor.

I really like the VTVM. It measure up to 1500 volts.  I have some amps with 600 volts on the plates and my cheapo radio shack DVM's only go to 500 volts.  Also it measure decibels but I haven' learned to do that yet.  Still reading an analog meter is yet another skill set.

I also like having more than one voltmeter, so I can continually monitor one voltage, while spot checking other voltages in an amp.