Mysterious electronic do-dah identification help.

[dave walsh]

As said in 58* Catfish [49*], the AR88 has a notoriously sensitive output transformer circuit that can blow and cause a very serious cascade fault even in a well maintained set kept in a good environment, if the right spkrs aren't hooked up properly. Using headphones can be a shocking experience as well I can't believe that it's been run recently.

It's a basic rule for vintage gear, never mind items in this condition, that applying power is the last thing to do-even if you know what you're doing

The 301 deck could be your best best find so far but given the destructive salty atmosphere. Can you show us the underside? I sold one once but the purchaser found it was for 60 cycle mains operation [ie USA] not [50] UK which affects the speed. He kept it though. That's probably the one difficulty you won't have.

Dave W

[BlueCatfish]

Originally Posted by Radio Wrangler

You have to remove the screws and the trim strips that run up the sides of the front panel. The receiver can now be slid out of the cabinet. Look on the sides of the receiver, there is a triangular bracing gusset on each side. They used to stick modification labels on the outside faces of these.

The meter fitted in your black AR88 looks to be a British "Peak Programme meter" which was thing for measuring sound signal levels a lot more advanced than the American VU meter. the 0 to 7 scale is a dead give away.

David

Nothing there. It looks internally exactly the same as the other that's not been rewired except for the different meter.

[BlueCatfish]

Originally Posted by dave walsh

As said in 58* Catfish [49*], the AR88 has a notoriously sensitive output transformer circuit that can blow and cause a very serious cascade fault even in a well maintained set kept in a good environment, if the right spkrs aren't hooked up properly. Using headphones can be a shocking experience as well I can't believe that it's been run recently.

It's a basic rule for vintage gear, never mind items in this condition, that applying power is the last thing to do-even if you know what you're doing

The 301 deck could be your best best find so far but given the destructive salty atmosphere. Can you show us the underside? I sold one once but the purchaser found it was for 60 cycle mains operation [ie USA] not [50] UK which affects the speed. He kept it though. That's probably the one difficulty you won't have.

Dave W

It's going to need a little evapo-rust on that side. The input says that it can be wired for 120 or 240.

[turretslug]

I think those four small holes in the top of the front panel of the grey AR88 are where the identity plate would have been, like this one. Shame it's missing, the Air Ministry logo gives it a certain stiff-upper-lip gravitas.

[Radio Wrangler]

In the AR88 there are two capacitors connected in parallel (why two? probably making up the needed value from stock items, at a guess) acting as a DC block from the 6SG7 audio amplifier to the 6V6 audio output stage. If either goes leaky (well, when one goes leaky. They are notorious) this makes the 6V6 grid go positive and the valve turns on more current.

It doesn't do the valve any good.

It very often destroys the output transformer (far harder to get a spare than a 6V6)

It has even been known to burn out the mains transformer.

So you replace these capacitors before firing up an AR88

Also, do not fire it up without either headphones plugged in or a speaker connected... that fragile output transformer again. Valve audio stages tend to over voltage and die if worked into an open circuit. Transistor audio stages tent to over current and die if worked into a short-circuited load.

Once gone over, the AR88 is a very fine sounding radio on AM broadcasts. It works well receiving Morse, and with care can be made to receive SSB.

The famous enigma signals that were intercepted then passed to Bletchley park for decoding were received on a mixture of HRO and AR88 receivers spread around the country. Some in listening posts, many in private homes.

David

[Uncle Bulgaria]

I'm near Truro, so can possibly be roped in if there's a pressing need that things will otherwise be dumped, and there's an interest here. I can probably hold onto things until better times. I can imagine there's not much travel happening, and many members are shielding. I could also be interested in the Hunt's Analyser. A 301 would be fun to restore, but I fear I cannot rise to the kind of prices people pay for these on eBay.

[BlueCatfish]

Originally Posted by Cobaltblue

The Garrard 301 on the other hand does fetch a tidy sum.

Cheers

Mike T

So, do you know much about the difference between a series 01 and 02? I've seen a few 02's go on eBay and made like £1300 for parts and what, in much better condition than mine. But my listing was live 14 minutes and I was offered £920...Which is way more than I'd figured given the rust and stuff.

[Radio Wrangler]

It looks like the purpose of this thread has been met, the items have been identified except, I think those two chassis.

I think the value of the turntable may have come as a very nice surprise.

Anyway, the forum has a strict rule about not discussing items on auction sites, and as the turntable is now on Ebay, it falls under that rule. This is an open forum and both sellers and bidders can look on here and if they see discussion of an item they are bidding for, there is a risk that things could get contentious. There has been such an occasion, which resulted in the creation of that rule.

There is a for sale section on the forum, but only for items with a set price. Usually, though, if money is the main requirement, ebay etc will prove more successful.

But as things are moving from the identification phase to the selling phase, it's time to close this thread.

Some great finds!

David