Valve radio help needed

db · Post by db » Fri Sep 04, 15 10:33 pm

I'm having a bash at getting this thing working. I've cleaned out 70 years of crud and replaced a few rubber insulated wires that had rotted.
There's power through it as the bulb behind the display lights up, the tuner and other controls are mechanically ok.

The main issue is valves. The big one's missing and some of the smaller ones look blackened so may be blown?
The valve numbers are all stamped on the radio chassis but so far I've not found one of them on any vintage valve site I can find on the net. Anyone familiar with this stuff? (I'm assuming it's Canadian made by the label in photo 3)

Valve no's are-
AQ5
X4
CR6
BD6
BE6
27D532720 (this is the big one that's missing)

Jeff · Post by **Jeff** » Fri Sep 04, 15 10:46 pm

Hmmm. 3 weeks ago I coulda probably picked them up for you.

ok, you need to cross ref them, there maybe alternatives available. All this info is on the web. Now, you may find some on eBay, if you do, make sure they are not from China. They are manufacturing some really bad tubes. Also check bases, they are prone to break up. If you still can't find any. Pm me with numbers and any info you find out. I can probably pick some up from the ham radio shows I attend, or some of the guys in my local club.
Blackend tubes do not mean they are blown, years of use can cause that. But be aware, just changing the tubes may not fix it, but can be a good place to start, what radio is it? Interestingly looks like a Canadian issue.

db · Post by db » Fri Sep 04, 15 11:10 pm

Thanks Jeff, that could be a big help!!
This is one of a bunch of old radios I picked up in a job-lot. There's 14 altogether, mostly 60's/ 70's stuff, this is the only valve one.

I've tried cross reference sites but I can't find these numbers listed anywhere. Do you know of any US/ Canada sites I could try?

Gareth · Post by **Gareth** » Fri Sep 04, 15 11:18 pm

Paul, search for "tubes" along with the reference numbers that you have as well as "valves". You should be able to find equivalents for what you need but they can be a bit pricey. Try this link for a bit of research.

http://www.worldtubecompany.com/mm5/mer ... e_Code=WTC

db · Post by db » Sat Sep 05, 15 12:00 pm

Thanks Gareth. I stumbled across the answer- the stamped numbers were all missing a '6' prefix. I've found them all on eblag now between £7-10 each, lets hope I don't need all six!
No luck with the missing valve yet though. I emailed a guy in the US so lets see what he turns up...

TW71 · Post by **TW71** » Sat Sep 05, 15 8:01 pm

Bottle bashing time eh!

You will probably find that the capacitors / electrolytic's have shifted value or are leaky and the resistors shifted value (anode ones I expect!) due to heat and high tension supply over the years.

Good luck

Mick70RR · Post by **Mick70RR** » Sat Sep 05, 15 9:35 pm

We got any more radio amateurs in the club. I've been licensed since 1982 and currently use a Ten-Tec Omni VII. I don't even have a mic for it, I only use the key.

G4OPE

db · Post by db » Sat Sep 05, 15 10:04 pm

Ha ha, I'm a radio professional and I've no idea what you lot are on about

Modern BT radio kit is plug n play so I don't learn much.
I suspect I'll throw a bunch of time and money at this thing and get nowhere but hey, gotta try

TW71 · Post by **TW71** » Sun Sep 06, 15 2:35 pm

Mick70RR wrote:We got any more radio amateurs in the club. I've been licensed since 1982 and currently use a Ten-Tec Omni VII. I don't even have a mic for it, I only use the key.

G4OPE

I have been interested since '68 in RF and SWL but never took the license, about time maybe but would like to read the morse first. Always was in electronics mainly test and measurement, back when you could build your proper home brew kit!

I think there is another G license in the MMA. 73!

db, you may be right regards to time and money! careful of the HT if you are going to get serious and try to get a circuit diagram!

Mick70RR · Post by **Mick70RR** » Sun Sep 06, 15 3:36 pm

TW71 wrote:
Mick70RR wrote:We got any more radio amateurs in the club. I've been licensed since 1982 and currently use a Ten-Tec Omni VII. I don't even have a mic for it, I only use the key.

G4OPE
I have been interested since '68 in RF and SWL but never took the license, about time maybe but would like to read the morse first. Always was in electronics mainly test and measurement, back when you could build your proper home brew kit!

I think there is another G license in the MMA. 73!

db, you may be right regards to time and money! careful of the HT if you are going to get serious and try to get a circuit diagram!

No valves in this rig.

Dave999 · Post by **Dave999** » Mon Sep 07, 15 9:37 am

OK valves have a thing called a getter

a getter is the silver bit on the inside of the glass. looks like silver paint

over the life of the valve it is designed to suck up any stray vapours produced by the metalwork as it heats and cools

on an old valve it will be black with an orange rim to it

on a new valve it will be silver

on a valve with no vaccum at all it will be white powder

a valve with a black getter will still work, and when it is a small signal valve like those in your radio possibly for many many years. its performance will be degraded but it will still work

if you buy new valves look for a silver top, that's no guarantee that the the valve is mechanically sound, but is an indicator that it has a good vaccum in it and has not ruptured or leaked.

your missing valve number doesn't seem to be a valve number

however a 4 pin valve like that is going to be a rectifier valve -> a diode

or a directly heated triode (unlikely, that's 1920s/30s technology and the rest of the radio looks to be 50s/60s)

because of the 12 volts supply in a car you will either have special valves that work on a 12 volt DC heater rather than 6.3 volts AC

or that radio has some major power supply built in that will use some kind of vibrating circuit to crank the 12 volts up to 400 volts square wave AC then rectify it down to a dc 6.3 volt heater and 150-300 VDC for the valves.

you will be able to find all of the valves it just takes time

who made the radio
what is its model number

Dave999 · Post by **Dave999** » Mon Sep 07, 15 9:44 am

thought the socket was a UX4 but its not

Oh actually it might be

http://www.hificollective.co.uk/content ... alve-bases

Dave

Dave999 · Post by **Dave999** » Mon Sep 07, 15 10:05 am

you already know about the missing 6

27D532720 there are numerous 27D and numerous 427 and 627 valves but all are 1920-1945

i.e too damn vintage

but they were made by Westinghouse which is US/Canada

Dave

Dave999 · Post by **Dave999** » Mon Sep 07, 15 10:13 am

Plymouth Motorola 27D car radio ??

Dave

db · Post by db » Mon Sep 07, 15 10:19 am

Great info as always Dave

The patent sticker is Canada 1937-1955 so could they have used the early workings up to '55?

I'm suspecting now that the number stamped on the casing by the missing valve is the part number of the casing, even the patent label has a similar part number!

All the valves I still have look mechanically good, I see no white bits.