Ah the friction drive I am told you should sand the edge or the disc to blunt it and slightly press the outer discs in with a pair of long nose pliers.

This friction drive is different - it's mostly encased in a steel cage so you can't really get to the disc, and the outer edges are not visible at all. I know what you mean though - the other 3 radios had the more common type.

Now I may as well describe the remaining cleanups which will take a few more weeks, just to bore everyone.

1. A Radiola that belonged to my stepmother before her untimely death, so I'd like to keep it working if at all possible. I couldn't make out the model number, but the valves are the usual 7-pin set. It worked, but just not as sensitive as I'd like. When originally received the 6AQ5 had been replaced by a N78, but I did eventually change it back. The 22k resistor on 6BE6 G1 had risen to >30k, so it was replaced. I then decided on the tuneup which I described in one of Fred's threads. I always thought that one of the coils had a problem because adjusting it didn't seem to make any difference, but on the voltmeter it did tune to the correct position. It seemed to work better after that. I also gave it a clean as it had been in the garage for a while and gotten rather dusty. It looks much better now.

2. A Radiola (post #22) which had been sent to be scrapped. I turned it on and got a few crackles suddenly followed by silence and things began heating up more than they should. Checking the dynamic speaker showed it was ok. This radio has heaps of black caps and rubber wires. The troublesome bandswitch takes up half the radio with large numbers of inaccessible parts. Therefore I decided to proceed with the scrapping. This radio was badly designed with the tuning dial, front lights, and band indicator on a separate plate screwed to the inside of the cabinet, and the screws are hidden behind the radio chassis. Of course I broke the dial cord while trying to get it all out.

3. The STC 5150 Timatic (post #28) also had been sent for scrapping. Even though STC was a local company, the valves were all Brimar ones (made in England). The back panel was smashed to bits so I threw it out. The radio itself seemed to work ok though, and the knobs were all there, so I decided I'd keep it after all. Then it started cutting out, and I tracked this down to the vicinity of the 6AV6. Wobbling the valve caused disruption so I swapped it out, and also made sure nothing was touching something else. After that it works very well indeed, not needing an external antenna to pick up lots of country stations. As usual the clock had burnt out and was disconnected.

One of the most common causes of IF transformers seemingly failing to calibrate, is due to cramming too much signal down its throat causing the AGC / AVC to cut in. If it does your doomed. In many cases you are, if you know the tube, better off calibrating on SW if fitted as tubes such as 6A8 are destabilised by AGG and it is not applied to the Pentagrid on SW. However, it may still be applied to an RF amp, or pre amp.

Marcc

I thought I'd waste a few hours looking at a turquoise Astor that had been scrapped ages ago but never thrown out. There wasn't any notes, so I had to start over. So, no knobs, no power plug, and no valves.

Found some valves (6BE6, 6BH5, 6BD7, 6M5, 6V4). The socket for the 6BE6 broke, but not badly enough to stop it working. Fitted a plug. No power. Power transformer was burnt out. So I replaced it with one from the scrapped Philips. Still nothing. The power switch was burnt out on both poles. Joined up the wires for now. Decided to replace the cap and resistor on the anode of the 6BD7, they were both completely out of tolerance. Applied power and at last the valves lit up. Did a few power cycles to initialise the electros. Voltages were low. The 0.1μF cap on the B+ line was warm, so snipped it out. Voltages came up ok. No sound. Speaker was blown, hooked up the test speaker for now. After doing some voltage checking, it seemed the 6BH5 wasn't drawing any current, so replaced it. At last I could hear some stations at low volume. Enough for tonight, I need to decide if it's worthwhile to continue next week, or just dump it.

Things wrong:
- No knobs
- No on/off switch
- No dial lights & sockets
- All the numerous wax caps to replace
- Probably half the resistors to replace
- New socket for the 6BE6
- New speaker
- Reattach the various felt pieces around the speaker that fell off
- Both IFTs have broken jammed slugs
- Volume and tone controls are clapped out, need replacing

What do you think I should do?

Hi Rob, sounds like a spare parts chassis to me!

It all depends on how desperate you are to have one of that model in the collection.
That is the sort of wreck I delight in fixing, but do you really need it?

Fred.

Sounds like it will buff out lol. A real silk purse.

Hi Robbbert,

I admire your tenacity .... I would have stopped at "power transformer burnt out, no valves, jammed/broken IF slugs, speaker blown" .

As Fred says, it depends on how badly you want that model and how close to 'original' you want it ....?? I am not a Collector per se, but I have to admit to 'going over-the-top' on a couple of items of equipment that were important to me ....

An alternative, assuming you wish to display the casing/cabinet ... can you install a different, working chassis ie. change pot shaft positions on the chassis, or, strip the chassis and use a digital AM chip etc ... ?????

Cheers,
Ian

Before even thinking about power, the set is assessed. At trap is globe sockets. It is often better to have a dead globe than none as some are spring loaded and that spring can cause a short.

Marc

That blue Astor did make it back to the scrap pile. I have a yellow one of the same model which has a bit missing out of the case. Perhaps I could swap cases? I need to see if the blue case looks nice enough.

1. Next from the scrap pile is a HMV 63-53. This is a clock radio that looks nice from the outside, but is rather cheap and nasty inside. Valves: 6BE6, 6BA6, 6AV6, 6M5, 6X4. This one had a note inside, so I could see what was wrong. The major problem was the power transformer which while it hadn't burnt out completely, was well on the way with smoke and sparks coming out, and fluid leaking out. Being cheap, it wasn't screwed in, it was soldered in, and my little iron isn't beefy enough to melt the solder.

Other issues: power switch missing, had been bypassed ages ago. Clock damaged by someone's screwdriver or something, bits of winding hanging out. It had been disconnected. The speaker transformer was open-circuit. Case damaged underneath. Could be more, but since I didn't plug it in I thought that was enough.

2. The next one never had a case, it looks old with a large square dial that says Midlands. Dial pointer missing. No valves. The sockets are all 7-pin, so there's only one set of valves for that (6BE6, 6BA6, 6AV6, 6AQ5, 6X4). In fact it works, but it will never be presentable. Maybe it was someone's homebrew.

3. Lucky (or unlucky) last one. Tela-Verta TV-14A. Uses octal valves: 6J8G, 6U7G, 6B6G, 6V6G, 5Y3G. I might be mistaken, but these radios don't seem to be very common. All the coils around the 6J8 are wrecked (i did it, didn't know what I was doing back then). I don't know anything about replacement either - perhaps something might be in the scrapyard. The dynamic speaker worked last time it was tested. Despite the foreign-sounding name, Tela-Verta was at Chatswood (Northern suburbs in Sydney). If there's any progress I'll post it here.

Tela-Verta: It powers up, the audio section works. But the oscillator coils for both SW and MW are damaged, probably beyond repair. I found a MW coil in a scrapped Radiola that uses the same frequency changer valve, so I will give it a try, next week. Probably not worth worrying about the SW.

Not exactly happy with that last comment. Just because its the same tube it's not in any way a guarantee that it will be satisfactory.

The coils & tuning capacitor are a matched set which are aligned & calibrated to track in manufacture. Therefore, should the tuning gang in the donor set be different to the repair one. It may not track properly.

Now what did you do to the existing ones? Photo perhaps.

Marc

I looked again at the existing MW osc coil, it has 2 windings, one thicker than the other. All 4 lead-in wires are snapped off the pins, but 2 of them come together which I assume would be the common earth. However I don't know which winding is the primary or secondary. Any ideas? Or should I guess?

My problem is I can't really see the wires clearly.
Nevermind, one of the supposed earth wires was a shadow, the wire is just not there or broken off.



With the SW coil it's obvious an overload went through one of the windings and fused it, because the wax melted. The part of the winding that's still there has shorted to the other winding, and there's a piece of stray winding just hanging about, broken off, not connected to anything except its pin. I think it was already like this when I got the radio, but I can't really be sure - it's been a while.

Well... the coil from the Radiola was no use - the adjustor is part of the chassis and cannot be removed. The coil can be unsoldered and removed though, but without the adjustor it's no use. So I looked in other wrecks, but nothing came close. Then I found in a pile of bits something that nearly fitted, so I wired it in so it was held in by the wires. And - it works. But the sensitivity is terrible, so I can only get my station and a very faint 2FC. The top adjustor on IFT2 does nothing, so maybe a dud there too. There's a few parts that got disconnected in that area ages ago.

There's something wrong with the connection between the IF and the audio too, touching the 6B6G top cap makes lots of hum, but the radio volume is quite low.

I'll keep looking...

Progress... the top coil of IFT2 was open-circuit - this caused the audio diode to be disconnected. Everything is shrouded in black wax, but I was able to determine that the break was about 15mm above one of the terminals. So all I could do is poke around with the iron until continuity registered on my meter. This improved matters in that I could now tune IFT2.

Next, the main tuning didn't cover the full range, so I changed the 435pf cap to 560pf, and then removed the wirewound trimmer to get the frequencies up into the right slot (520 to 1610 kHz). Then, I found the aerial core adjuster barely does anything, although the coil conducts correctly. I've left that for now. Again I had to remove the aerial wirewound trimmer to improve reception a little.

Then I added a goat shield for the 6U7G, to calm the incessant need for spurious oscillation. I tried a replacement ECH33 and a ECH35 for the 6J8G, I settled on the ECH35 as it seemed to handle the power of my station just a little better than the others.

So, in the end, it receives my station just fine, and a bunch of ABC stations at the bottom of the dial. The middle and top of the dial is quite deaf (for example it can only just receive SEN with the main aerial, as long as the station registers over 9+10db on the comms receiver). Nothing at all can be received without the outside aerial, but this could be because unusually, the aerial coil is in a can.

I added dial lamps, and put the radio in its case, only then did I find out that the dial pointer is out a bit, oh well, I'll fix it later. A couple of knobs were also added, so the thing at least can be used somewhat.

The case can get cleaned tomorrow. So, this is one (rare?) radio which has been saved from the scrapheap.

I did a bit more with the Tela-Verta last week - the last remaining old caps were replaced. The ancient resistors were amazingly all within tolerance. The power cord had entirely rotted and had to be replaced - I was very lucky that I hadn't had a fire or worse. More testing proves the insensitivity is somewhere within the aerial coil, because if I bypass it then suddenly it all works fine. The last other issue is at the higher end of the band, some feedback noises become evident, and the trouble is around IFT2. Putting my finger in the area (in the air) makes it worse. Stations can still be received though, it's just these other noises are there too. I've put that radio aside for now. Still, it works much better than when I first obtained it - all it could do was make strange chattering noises - it was receiving them, but I never found out from where.

Today I looked at my Airzone 6641A (Concert Star) in its nice shiny case. Valves: 6A8G, 6G8G, 6V6GT, 5Y3GT. The problem has been from the start that the dial drum, dial glass, front labels and knobs were missing. The dial cord was also broken. The dial drum is a special one, I have nothing that fits. Without it the radio is useless. Today I decided to look again, and I found a drum that almost fitted, it was just a bit too big. However, by juggling some hardware I managed to get it to fit on the shaft. Since there's no dial I didn't bother with a full dial cord exercise. Instead I just ran some fishing line from the tuning control to the drum - it works well enough.

But then disaster struck. When I went to put it back in the case, the too large drum now fouled the wooden panel that holds the speaker, and the radio wouldn't slide all the way in without jamming the drum. I could either abandon all I'd done, or just put up with it, which is what I chose to do. So I tuned it to my local station and left it in that position. Then the other problem showed up - the volume can't be turned right down. In fact on my station it's still loud enough to distort.

This radio has a spiderweb internal antenna mounted on top of the tuning capacitor. Without even using an external wire, it has by far the best performance I have ever heard on a 4-valve set, even outdoing many 5-valve sets. I really didn't want to scrap such a fine radio just because of some missing hardware. Even more amazing, all the components are original (except for the capacitor on the 6V6 grid), so it's full of ancient Chanex wax caps, and dot stripe resistors. Now I could change them all, but without a working dial there's not really much point. Anyway, another working radio to the collection.