Questions about a Avo VCM163

[mendipviews]

Hi everybody,
                     I purchased an Avo VCM163 Valve Tester from a local radio rally last week.
Knowing the troubles with meters and the like with the previous models is there anything I need to be wary of, need to replace, etc prior to plugging the unit in.

All help will be greatly appreciated and if anybody needs to test some valves and in the North Somerset area once its working please drop me a PM

Many Thanks
Luke

[Alan Douglas]

No problems with the meters on mine. I recall finding one metal-film resistor off value, that's about it. Marvelous piece of equipment. You must have been the first person to see it at the rally? Or maybe the only one to realize it was well worth the asking price?

[mendipviews]

No problems with the meters on mine.  I recall finding one metal-film resistor off value, that's about it.  Marvelous piece of equipment.  You must have been the first person to see it at the rally?  Or maybe the only one to realize it was well worth the asking price?

Hi Alan,
          thank you for the reply, I haven;t delved under the covers yet as I thought I would ask what sort of things to look for.
I thought of changing the capacitors but will wait and see what suggestions I get, I looked over at the VRRR forum and there was sugestion of resistor checking on a couple of threads on the tester but all and all it looks like a warm up on the variac and a suck and see approach.

No I wasn't the first to see the tester and there was some very low offers from other people but the seller was advised what would be a sensible price and thats pretty much what I paid for it. It came from a silent key and his daughter was selling off his equipment and parts and wasn't really sure on the price but had thought to ask the AVO man that comes to the rallies and I belive attends the BVWS.


Many Thanks
Luke

[ed731pdh]

These units are pretty bomb proof, both in design and construction. The unit I have came via a courier and you know what they are like for dropping stuff. A quick inspection found a transformer holding nut had dropped and was a bugger to get back in due to it's location, plus a quick mains plug rewire. Powered up and all ok. One word of advice, at the end of the day always park the meter needles by correct use of the switches to ensure their safety.

[Cleggy]

I own a 163 and having talked to other owners, their current condition seems to depend critically on the environment(s) they've lived in.

The gm meter on mine exhibits a low coil resistance and needs rather more than 50uA to get to go FSD and so I've adopted the well-proven solution of using an op-amp to recover the scaling. Also, the same meter has undergone a most peculiar form of corrosion on the plated (2BA ???) bolts which provide the connection out of the casing, those being covered in a white powdery material. Had to clean it off and cover them in Vaseline. In contrast, the meter on the LHS is perfect, which makes me suspect that one of them has been replaced at some time.

Cleggy