Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Voice of Music 990
#1

Just for something different I picked up a 1953 Voice of Music 990 record player for $20. Never fixed a phonograph player. If I mess it up no big deal and I get some useful parts. Strictly a casual project to see what one of these looks like inside. 

I’ve recapped this. Very easy to do. With  the layout the new electrolytic caps are just hanging in space which is bad practice but it should be OK. I replaced all the dried out bad wiring to the audio transformer, speaker, power cord. Wiring was awful - someone tacked it in place with a loop of solder. Took out the added phono jack. 
This was just something I fixed with some new caps I had in my parts drawer. Not exact values - I used a 22 mfd cap instead of a 20 - good enough. Can’t find my heat shrink tubing so I just used my normal electrical tape and plastic tubing on the electrolytics.

Once I did this it pulled about .44 amps at 110 volts which seems close to the 45 watts this is supposed to do.

The motor runs but the turntable doesn’t go. I plan to pay $10 and order a service manual. Some guy sells the instructions for oiling, motor servicing etc. About the mechanics of fixing this I know nothing but it seems all intact. All held together with these ugly little c clips which will have to be pryed off.

I have no illusions this is a restoration just casual Saturday morning tinkering. This service guy who sells the manuals and parts says “I don’t understand anything about the electrical when I asked him about the rectifier. Duh - if you care about these working you should.

My issue is this

 (1) It has a silicone rectifier. This needs to go obviously. I’m just trying to figure out what value of the dropping resistor I should use and where this should go.  I have a 1000 volt rated diode in the junk box.

(2) It has this 400 ohm resistor - this big honking wirewound pink deal which I assume is some kind of power resistor?? It should be replaced but I have no idea what wattage value. I’d assume a modern 10watt ceramic resistor would suffice.


Attached Files Image(s)
               
#2

Hello bridkarl ,
First all that power resistor helps drop the line voltage to supply the right about filament voltages to the tubes since between the two tubes there is 80 volt filament and our line voltage is roughly 120-125 AC .

That Set really needs a new powercord too plus that Square item with the fins on it is what they use for a rectifier it is what they call Selenium rectifier .
one thing is that they drop more voltage then the modern silicon rectifier so that power resistor R11 will need to be increased to high value .

Sincerely Richard
#3

Why does that 400 ohm resistor need replacing? Wirewound resistors are usually very stable. I wouldn't change it unless is was defective in some way. TAke care and BE HEALTHY! Gary

"Don't pity the dead, pity the living, above all, those living without love."
Professor Albus Dumbledore
Gary - Westland Michigan
#4

Yes, as Richard stated please replace that power cord. You can buy a 8' or 12' extension cord and cutoff the female end for a quick and cheap replacement.

Doesn't the service document you downloaded have the wattage listed for that 400 ohm resistor? If not I'd try something like a 25 watt chassis mount to dissipate heat. My guess is someone put in that big pink 400 ohm because the original went open or was getting very hot. Replacing the Selenium rectifier (if bad) might correct that.

John KK4ZLF
Lexington, KY
"illegitimis non carborundum"
#5

Hi Bridkarl, the filament string runs on 150ma. P= I squared x r so that 400 ohm resistor dissipates 9W. Go with a 20W or higher replacement if you’re going to do it!

Ron

Bendix 0626.      RCA 8BX5.   RCA T64
Philco 41-250.    Philco49-500
GE 201.             Philco 39-25
Motorola 61X13. Philco 46-42        Crosley 52TQ
Philco 37-116.    Philco 70
AK 35                Philco 46-350
Philco 620B.       Zenith Transoceanic B-600
Philco 60B.         Majestic 50
Philco 52-944.    AK 84




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 38-2 Automatic Tuning
I received my new 38-2 dial. I'm a little disappointed. As you can see in the picture the blues have a white shadow. The...dconant — 11:13 AM
Philco 38-2 Low Volume
I have been playing my 38-2 for a while now and it is doing very well. I did have to replace the 6A8 (osc) as it develop...dconant — 11:03 AM
Philco Speaker Spider
Hello, Does anyone with a 3 D printer make the spiders for those old Philco speakers? That might be a good idea for some...dconant — 09:41 AM
Philco 16B Parts
Hello, I'm looking to buy a 16B but I'm not so sure of what I am looking at. First as seen from the picture it looks lik...dconant — 09:17 AM
Looking for verification of correct schematic.
Klondike98, Thank you. I'll double check that SN and get back to you. GarySP, Thank you for the schematic.RossH — 12:13 AM
Looking for verification of correct schematic.
I think you have the correct take on your set. Ron's annotated early schematics that note the below B22000 serial numbe...klondike98 — 12:04 AM
Looking for verification of correct schematic.
Hello Ross. The Philco Radio Library located at the bottom of the page has the schematic with the tube count you have. ...GarySP — 10:48 PM
HiFi (Chifi) tube amp build - but my own design.
Tim It's be interesting if you put your schematic here. Who knows, you could get some advice from a few folks here. ...morzh — 10:01 PM
Philco 42-390, code 121 speaker
Thanks for that information. It would appear from the output transformer parts list that the transformer that was origi...Stevelog — 07:21 PM
Looking for verification of correct schematic.
I would like to verify that my thoughts are correct regarding my Model 70 and its appropriate schematic. My chassis inf...RossH — 06:26 PM

[-]
Who's Online
There are currently 1137 online users. [Complete List]
» 1 Member(s) | 1136 Guest(s)
Avatar

>