Valve radio help needed

Dave999 · Post by **Dave999** » Mon Sep 07, 15 2:11 pm

which possibly makes it a Plymouth Motorola 27D radio

and ive seen a circuit diagram today somewhere just can't remember what term I searched on

probably your valve number and radio valve

just can't find it now

I'm in a meeting for the next hour or so but I anticipate not fancying doing any work after that so will have another look

Dave

Dave999 · Post by **Dave999** » Mon Sep 07, 15 2:20 pm

http://www.radiomuseum.org/r/motorola_d ... guage_id=2

you will need to sign up

Dave

Dave999 · Post by **Dave999** » Mon Sep 07, 15 2:23 pm

naaa

valves look to big

Dave

Dave999 · Post by **Dave999** » Mon Sep 07, 15 2:27 pm

No its a Mopar motorola 833 (834, 835) (dodge, Plym ,de sot)

thus

http://www.radiomuseum.org/r/motorola_m ... dodge.html

sign up

circuit diag

valves will be listed

check euro equivalence

speak to Watford valves chelmer valve company or lanrex

and the smooth smooth sound of valves is yours to enjoy

Dave

db · Post by db » Mon Sep 07, 15 4:35 pm

Haha! Dave you're ace

Sadly it won't fit my dash, I might set it up in the garage tho!

db · Post by db » Mon Sep 07, 15 7:36 pm

I've had a quick look Dave, it ain't that one, mine has no preset buttons.
I'll have a proper look at that site this evening hopefully.

db · Post by db » Mon Sep 07, 15 9:20 pm

This is it- Motorola 5M Volumatic 1955

http://home.comcast.net/~vwradio/bigm/BigMRadios.htm

The missing valve is the vibrator tube you mentioned Dave-

The electronic design uses a mechanical vibrator tube to produce high voltage (~200 volts) through an oscillator, transformer and rectifier circuit. The 200 volts used to power tube grid elements. Vibrator tubes have contact “points” which wear out with use and commonly need replacement along with the buffer capacitor. The vibrator tube also has a low volume but audible “hum”.

Mick70RR · Post by **Mick70RR** » Mon Sep 07, 15 9:58 pm

Looking at your first picture, all six valves are in place so the missing component must be something else. My guess is another electrolytic capacitor but can't think why it would have three pins unless the third is connected to the case.

db · Post by db » Mon Sep 07, 15 10:50 pm

Thanks Mick, yes it's a vibrator tube that's missing. Daves post explains what it does

Mick70RR · Post by **Mick70RR** » Mon Sep 07, 15 10:56 pm

db wrote:Thanks Mick, yes it's a vibrator tube that's missing. Daves post explains what it does

Never heard of a vibrator tube. Good luck in finding one.

db · Post by db » Mon Sep 07, 15 11:35 pm

Yeah, I'm finding it's a bit tricky. aside from the problems of Googling 'vibrators'

car radio vibrators just don't exist.

This site - http://www.radiosforoldcars.com/whoF.htm states they've not been made for 30 years! They make new solid state equivalents. There's a couple of dealers in the UK so I'll try them.
I think my radio may have been made for VW so it could be 12 or 6 volt, pos or neg ground, the two main things I need to know before ordering!
I dread to think what it'll cost

Just found a Volvo version- http://www.ebay.com/itm/Vintage-1958-59 ... 1656586365

Dave999 · Post by **Dave999** » Tue Sep 08, 15 8:31 am

I guessed the 833 based on the valves....circuit might be similar

glad you found it....

If its a VW radio for VW America its negative ground and 6V until 1967

if you get the number for the vibrator there will be some some somewhere

or an adaptor so you can fit another type. with a valve circuit you'd probably be ok with a voltage 10% either side of the suggested 200.

when you first get it going... if it doesn't go bang... leave it sitting powered up for a couple of hours. but make sure you are on hand to keep an eye for smoke. however don't leave it on with no speaker connected

stick a 5 watt 16 ohm resistor across the speaker teminals or a speaker you don't care about. no speaker is like dead heading a fuel system makes life hard for the pump (your power valve)

those aged capacitors will drift in their capacitance once powered up again. as the plates (rolls of tin foil) inside move with the heat and charge

i.e what sounds bad may sound better or what sounds good may degrade with hum taking over

the vibrator is used to pulse charge a coil much like an ignition system charges a coil

the lumpy spikes that come out are then smoothed a bit and made into nearly DC hence the hum mentioned

couple of big silver vibrators on US ebay Yeehaa

Dave

db · Post by db » Tue Sep 08, 15 9:48 am

I'm finding a lot more info now I know what model it is!

There are two versions- 5M (6volt) or 5M-12 (you guessed it...)
Mine is the 12v, so not for a VW.
The radios were a universal model, you'd buy along with the fitting kit for your car (faceplate and knobs)

The instruction booklet below is on ebay, luckily it lists the valves on the cover so I don't need to buy it

The 6- valve prefix seems to indicate 6v, so mine are prefixed 12.

db · Post by db » Tue Sep 08, 15 10:47 am

Well these were certainly fitted in 53-55 Chevys, I've found fitting instruction manuals for those. No doubt some Mopars had them too.

This link has an amazing amount of information- it starts with an explanation to why Beetles exported to the US came without radios... European spec receivers could tune in to frequencies deemed illegal by the US!
http://www.thesamba.com/vw/forum/viewtopic.php?t=535705

5 =model year (1955)
M= manual tuner
12= 12 volt
Volumatic= automatic volume level (compensates for signal drop, etc)

The two little arrows on the screen are Civil Defense markers- tune in here when war breaks out!

Dave999 · Post by **Dave999** » Tue Sep 08, 15 3:13 pm

Ok so if they were in American Volkswagens
you will be able to get parts...

those guys are Original equipment mad...and in lieu of a standard Blaupunkt if the car had a Motorola all its life they are going to want a functioning Motorola again.

6 volt might be a problem....

if yours is 12 that's good for everything but your vibrator.

but a functioning 12 volt version for an oval window bug or Bus that has been upgraded for modern motoring i.e 12 volt electrics I think you might have a nice market for the radio if you want to sell.

Dave