AVO CT160 Valve Tester. Value and calibration?

[Ernest1]

Hi.

I have an AVO CT160 valve tester in very good condition. It was last calibrated in 1988 then stored. I think ex military. I really don’t think I’ll be using any time soon. Just wondering about calibration and or maybe selling it. Any thoughts?

Ernest.

[Dekatron]

Checking other auctions where they sold the same model is the best idea to get a current price figure, although sorting out the highest prices might be a good idea as those normally don't reflect the current going rate (some do but not all).

Check the auctions for if they guarantee that they are calibrated or only sold as spares is also a good idea to get an understanding for the going rate.

I can only recommend that you do a full calibration before selling yours and also that you check the condition of especially the meter, the grid volts potentiometer and the whole gm-wheel assembly and also have a look at all the rotary switches and the roller selector and sockets in the valve panel.

[woodchips]

Just to help Ramco, they sell ex-government stuff by auction, had about 8 of them for sale around Christmas time. These are untested, just as you see them, and I followed the auction until near the end so they all got at least £650 each. Now there is also a 15% buyers premium plus VAT, makes near 40% mark up, so paid about £1000 each.

One didn't sell and reappeared in the next sale, and got about the same.

[Ernest1]

Thank you very much Martin. Yes I would like to sell it knowing it was definitely ok. I just need to find someone who could do it for me in my area (North Devon) Uk.

[Ernest1]

Originally Posted by woodchips

Just to help Ramco, they sell ex-government stuff by auction, had about 8 of them for sale around Christmas time. These are untested, just as you see them, and I followed the auction until near the end so they all got at least £650 each. Now there is also a 15% buyers premium plus VAT, makes near 40% mark up, so paid about £1000 each.

One didn't sell and reappeared in the next sale, and got about the same.

Thank you , I noticed one on eBay for £1100 so that matches well with your experience. I would like to make sure it’s all fine first though but I’m sure it is. Is it a tricky job to calibrate them... if so maybe someone in the north Devon are could do it for me?

[Matthew kane]

It would be awesome if some of those businesses that help clear out ex-military or government surplus components had a stash of old AVO VCM parts (meters, transformers, pots, relays etc.). There's got to be some place out there with old surplus NOS parts still.

[Craig Sawyers]

You have to be very careful about buying a CT160, of all AVO valve testers, because operation renders the meter exceptionally vulnerable to burn out.

I would guesstimate that 50% or more of CT160's have a fried meter. So there is no way I would bid on a CT160 from Ramco, or any AVO valve tester for that matter, with operational status unknown.

Now I have bought several thing from Ramco, and if you pick and choose you can get good bargains, even with auction fees, shipping and VAT.

Craig

[woodchips]

I find this strange, an auction is an auction, it is cheap simply because you have no idea of the condition of the lots, you take a chance. So saying I would never buy from one is fine, just as long as you have the money to pay for the items others have bought and are now passing on. The only way of getting used to gambling at an auction is to do it. Don't do it as a one off event, you will be disappointed. My first auction buy was a small air compressor, everyone was laughing because they knew the piston and con rod were missing, what I wanted was the single phase motor, sniff test said it wasn't burnt out, I was happy.

I bought my CT160 from Ramco, must be 10-15 years ago, from memory I paid about £300 but only VAT to add to that. It looked new, took a chance, still not powered it up.

With all the help and assistance given on this site, thanks, I would have thought that a dead meter is a pretty unimportant failure compared with a busted roller switch or crisped transformer. Another meter with a DC amplifier solves the problem, not original, so what, it works.

[JonSnell]

Calibration can be carried out easily.
Just follow the instructions, armed with a few goodies, to make it as perfect as it can be.
I had a problem with a sticky thumbwheel.
Stripping it down, cleaning and a touch of dry silicon lubricant fixed that,
See page 9 for the calibration details. Hope it helps.

[Craig Sawyers]

Originally Posted by woodchips

I find this strange, an auction is an auction, it is cheap simply because you have no idea of the condition of the lots, you take a chance

Yes that is all fine and good - but I wouldn't call £1k for a CT160 with unknown meter condition "cheap".

Now I bought my CT160 with a known dead meter for £200. But there are other cheap pieces of AVO kit with exactly the same meter - I actually got one free. Different sensitivity. So you unscrew the scales and swap across, then use the op-amp trick to match the meter to the CT160 - job done. And it looks identical to the original.

Craig

[woodchips]

The word 'cheap' applies only to those who are bidding, not to you, you are not bidding because you don't think it is cheap.

There is a certain psychology to buying at sales, until you appreciate it and play by those rules then you will be disappointed. The most important rule is decide on a value, not price, and then work to that. Do not confuse being lucky, or knowing the seller, as the normal way things are sold.

[Dekatron]

You can always buy a second one, or a third or a fourth...... to get one in original state although with some swapped parts....

[David Simpson]

If Ernest wants to become an earnest member of the Vintage Radio fraternity, then perhaps he should get himself along to the next nearest BVWS Swapmeet, or Retrotek, or VMARS auction. Take along his CT160 and see what he can get. Prospective bidders could then make their own "sight-seen" offer.
CT160's & their problems must have taken up more reams of pages on this Forum than any other item of test equipment, over many years. So "Search" will reveal all there is to know.
Personally, I wouldn't touch a "sight-unseen" CT160 on eBay or any other online auction site with a barge pole. On the other hand, I did flog one(fully restored & calibrated) on eBay several years ago & made a tidy profit, having bought it cheaply(sight-unseen) from Gerry Horrox, in need of a lot of TLC. But then I, like many others, trusted Gerry. Furthermore, I also supplied the purchaser with two free standardised valves & their corresponding A4 Ia/Vg Graphs. He was over the moon.

Regards, David

[Craig Sawyers]

I bought mine from Gerry, the one with the open circuit meter. Hi price reflected that fact. I'm close enough to Crowthorne that anything I've bought from him just involves a half hour drive.

He's one of the good guys.

Craig

[Station X]

Mine also came from Gerry and he pointed out to me that the meter was sticky.

It was initially repaired by The Herts Meter Co and subsequently replaced with a Simpson tautband movement.

[David Simpson]

In fact the 2 CT160's I used to have both came from Gerry. The 2nd had had a bodged op-amp jobby done on it by a customer, then returned. Hence dead cheap. But then I ran it with a 444uA meter out of a phooked MK1, via a op-amp from Jeremy O. Worked a treat.
Gerry, Jeremy, Mike B, and one or two others, set the benchmark for trusted AVO VCM dealings in past years. Nowadays, in view of certain recent missfortunes to two or three VCM's, I feel inclined to advise folk to thoroughly examine the provenance & reliability of these expensive items.

Regards, David

[Matthew kane]

Prices have all but risen for any thing listed on your typical marketplace websites, ebay, yahoo auction JP, etc for AVO's, Funke's and sought after Hickok models.

It's kind of sad seeing people bidding/paying $1.5k + for such testers that are sold from deseased estate sales or show signs of tampering (missing chassis screws or knobs).

[Ernest1]

Originally Posted by JonSnell

Calibration can be carried out easily.
Just follow the instructions, armed with a few goodies, to make it as perfect as it can be.
I had a problem with a sticky thumbwheel.
Stripping it down, cleaning and a touch of dry silicon lubricant fixed that,
See page 9 for the calibration details. Hope it helps.

Many thanks! I had a few lessons on the avo from Kind member on the forum and be keeping it as so useful. Yes, the thumbwheels. I discovered its a tricky job , but not the trickiest of done😁.