AN/GRR-5 Filament Voltage getting Low when Receiver is working

[Charcoal01]

Hi there,
I have a Problem with my Angry 5.After a while (5 minutes) my Receiver is working,the Filament Voltage is getting lower and lower.I already checked te both Vibrators,cleaned and realigned the contacts.
Has someone an idea?
By the Way,what Antenna ist the best for the Receiver?

Thanks and best Regards
Timo

 

[CMPPhil]

Which power source?

Cheers Phil

 

[Charcoal01]

I used the 6v and 12v Power source.
Best regards Timo

 

[CMPPhil]

Hi

These are great radios, just about the end of tube type radios used by the US military. One I had developed the same problem will look at my manuals to see if I made any notes as to the cause. Do remember that it was a heat related problem in that it would work for a longer period if the two sections of the radio were out of the case.

Have you measured the fillment voltage, memory is saying it is pretty low want to say 1.5 volts.

Maybe some other real radio guys could jump in now with suggestions.

Cheers Phil

 

[Charcoal01]

Hi Phil,
Im a little bit related with tube Radios,but this Problem i've Never had.the Power Supply was s
out of the Case when i switched it on Power,filament Voltage was 1.70 volts.then i tuned it with the poti down to 1.40volts.as it was written in the manual... After a while ,about 6-7minutes it started to went lower down to 0,8Volt,by that,the receiver quit working....
It's Really a great Radio,and rare in Germany,so i Hope i find Here some help to made it Work
Best regards Timo

 

[Charcoal01]

Hi Phil,die you find something in your Manuals about my Problem?
Timo

 

[cagosti]

There is a stack diode in the bottom of the case you will see it when the power unit is slid out. Make sure it has been replaced with a modern type

 

[CMPPhil]

Hi
Have not had chance to get the AN/GRR-5 out one the bench to see how I fixed mine when I had this problem. I have a couple AN/GRR-5s and cannot remember which ones are working.

The comment on the diodes is a good one.

For a couple years in the 80s we had AN/GRR-5 in the house so we could listen to shortwave broadcasts from BBC, CBC etc. and had this same filament voltage problem for while I wired in D cell battery holder in to the circuit and just replaced the D cell as needed.

Your post has got me wanting to get my AN/GRR-5 back into my MVS as working radios, good project for bad weather.

Cheers Phil

 

[Charcoal01]

Hi Phil,
Thanks for your answer,is this diode on the bottom of the housing,wired in the connecting cable from receiver to power unit?
The more i use the receiver the longer it will keep working.but its still stop working after a while.
Its a great radio,i have it in my living room connected with a long wire antenna in my garden.what antenna did you use in the 80s?we dont have any short or medium wave radio stations in germany since some years ago,but i receive a lot of stations still hin europe.a nice thing on cold,dark evenings
Cheers Timo Boll

 

[Charcoal01]

@Cagosti :
What replacement did you choose for the Stack diodes/selenium rectifiers in the bottom of the case?cr102/cr101

 

[ke6rwj]

You can see how i replaced all the selenium rectifiers in this writeup --> http://radionerds.com/index.php/AN~GRR-5 .


The diodes to replace the ones in the case are not that large at all, they don't take much juice, actually they are quite small. Remember to just remove the ones from the case, so they don't short.

ALSO BE VERY VERY CAREFUL WHEN PUTTING THE RADIO AND PS BACK IN THE CASE. THE PLUG IN THE BACK IS NEAR IMPOSSIBLE TO REPLACE.

Chris

 

[Charcoal01]

Hello,and a Happy New Year!
I fixed my loosing filament voltage Problem:i renewed both capacitors C110&C111,and now i have a constant filament voltage choosed to 1.45v.