I have collected lots of info. on the RCA AR8711 Radio Direction Finder and it seems as though the B+ voltage is supposed to be 230VDC. I'm getting the schematic which might help.
Anyhow, I have hooked up the wires to the 21 tab Jones plug and have tried to make things work as best they can with: i) a 5VDC, 3 amp power adapter--as close to the filament voltage (6.3) as I can ii) various battery 'power packs' I have made using modern rectangular 9VDC batteries I have hooked together in series. I'm not sure what the amperage would of those would be. I've tried inputting 180VDC or 225VDC as B+
The problem is of course that I need to get hold of a proper 'house voltage' Variable Power Supply (I'm looking for an EICO 1030 or a PACO B12 unit). However using the battery packs @180 the set works very faintly. When I put my ear to the speaker I can hear strong stations on BC, but quietly, at the edge of audibility. I have wiggled the tubes etc. The green 'tuning eye' indicator is on. Interestingly, @225VDC there is really no difference--the volume is still very, very low and no louder than at 180.
This set appears to be in mint condition cosmetically and the tubes test great. So, as before, any 'Sherlock Holmes' advice on likely gremlins would be most helpful. I'm making a guess that a 180VDC homemade battery pack might just not pack the amperage.
It just seems as though the set is suffering from power/current starvation, and does not have enough to activate the audio amplification stage to the required level. Why the 180VDC B+ works at the same level as the 225VDC is a mystery--to me at least.
Have a great day,
Leslie
:I have collected lots of info. on the RCA AR8711 Radio Direction Finder and it seems as though the B+ voltage is supposed to be 230VDC. I'm getting the schematic which might help.
:
:Anyhow, I have hooked up the wires to the 21 tab Jones plug and have tried to make things work as best they can with: i) a 5VDC, 3 amp power adapter--as close to the filament voltage (6.3) as I can ii) various battery 'power packs' I have made using modern rectangular 9VDC batteries I have hooked together in series. I'm not sure what the amperage would of those would be. I've tried inputting 180VDC or 225VDC as B+
:
:The problem is of course that I need to get hold of a proper 'house voltage' Variable Power Supply (I'm looking for an EICO 1030 or a PACO B12 unit). However using the battery packs @180 the set works very faintly. When I put my ear to the speaker I can hear strong stations on BC, but quietly, at the edge of audibility. I have wiggled the tubes etc. The green 'tuning eye' indicator is on. Interestingly, @225VDC there is really no difference--the volume is still very, very low and no louder than at 180.
:
:This set appears to be in mint condition cosmetically and the tubes test great. So, as before, any 'Sherlock Holmes' advice on likely gremlins would be most helpful. I'm making a guess that a 180VDC homemade battery pack might just not pack the amperage.
:
:It just seems as though the set is suffering from power/current starvation, and does not have enough to activate the audio amplification stage to the required level. Why the 180VDC B+ works at the same level as the 225VDC is a mystery--to me at least.
:
:Have a great day,
:
:Leslie
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Leslie--
You will need at least 6 volts DC or 6.3 volts AC for the filaments; the tubes won't operate properly without it. The brightness of the eye tube should vary with the B+; I believe 180 volts is too low--should be 220-230. Did you replace the electrolytic capacitors? On mine, the 2 10uf that go to the audio tubes (12AX7, 6AK6) were bad. Just replace all of them; they are close to 60 years old. Also, the couplate may be bad; you can test it by jumpering a .01uf cap from pin 1 of the 12AX7 to pin 1 of the 6AK6 to see if volume increases. Also, get a headphone plug and plug it into the phone jack several times; it may be dirty.
Johnnysan-
Many thanks for that. I'll try the tips you suggest, and I have replaced the 3 electrolytic capacitors in the AR-8011.
As you have one of these sets it would be great to contact you from time to time if that would alright (I can send you my email if that would help).
Mine, as I think I mentioned, seems to be virtually unused and is in great shape (except for the volume problem described). If you want to check anything using images of my set for comparison/structure etc. I'd be pleased to do that. I'm getting the schematics from another helpful Radiomarine owner.
Do you have any idea where I could get a copy of the Manual (I have a saved search on Ebay)? A 21 pin Jones plug?
As I found out (DUH), the amperage of batteries wired in series does not increase (just the voltage), so my 225VDC battery pack probably just does not have the 'oomph' to make the tubes run properly.
I'm trying to find an EICO 1030 or PACO B12 to give me some stable voltage output to do my testing with. I really do reckon I've got a kind of 'current starvation' on the set.
Cheers, and have a great day.
Leslie
:Leslie--
:You will need at least 6 volts DC or 6.3 volts AC for the filaments; the tubes won't operate properly without it. The brightness of the eye tube should vary with the B+; I believe 180 volts is too low--should be 220-230. Did you replace the electrolytic capacitors? On mine, the 2 10uf that go to the audio tubes (12AX7, 6AK6) were bad. Just replace all of them; they are close to 60 years old. Also, the couplate may be bad; you can test it by jumpering a .01uf cap from pin 1 of the 12AX7 to pin 1 of the 6AK6 to see if volume increases. Also, get a headphone plug and plug it into the phone jack several times; it may be dirty.
:Johnnysan-
:
:
:Many thanks for that. I'll try the tips you suggest, and I have replaced the 3 electrolytic capacitors in the AR-8011.
:
:As you have one of these sets it would be great to contact you from time to time if that would alright (I can send you my email if that would help).
:
:Mine, as I think I mentioned, seems to be virtually unused and is in great shape (except for the volume problem described). If you want to check anything using images of my set for comparison/structure etc. I'd be pleased to do that. I'm getting the schematics from another helpful Radiomarine owner.
:
:Do you have any idea where I could get a copy of the Manual (I have a saved search on Ebay)? A 21 pin Jones plug?
:
:As I found out (DUH), the amperage of batteries wired in series does not increase (just the voltage), so my 225VDC battery pack probably just does not have the 'oomph' to make the tubes run properly.
:
:I'm trying to find an EICO 1030 or PACO B12 to give me some stable voltage output to do my testing with. I really do reckon I've got a kind of 'current starvation' on the set.
:
:Cheers, and have a great day.
:
:Leslie
:
: :Leslie--
::You will need at least 6 volts DC or 6.3 volts AC for the filaments; the tubes won't operate properly without it. The brightness of the eye tube should vary with the B+; I believe 180 volts is too low--should be 220-230. Did you replace the electrolytic capacitors? On mine, the 2 10uf that go to the audio tubes (12AX7, 6AK6) were bad. Just replace all of them; they are close to 60 years old. Also, the couplate may be bad; you can test it by jumpering a .01uf cap from pin 1 of the 12AX7 to pin 1 of the 6AK6 to see if volume increases. Also, get a headphone plug and plug it into the phone jack several times; it may be dirty.
::Johnnysan-
::
:
Do you still need the shematics of the AR 8711 and power supply?
I've got one original and I can Copy it if needed .
Hervé from France
Ok ??
Just to let you know that I'm getting a Radiomarine ET-8044 (the 'sister' transceiver/radio telephone set that went with the AR-8711), if that's of any help (i.e. with regard to sending compare/contrast structural images of the setup).
I imagine finding the original RCA power supply for the 8711 is virtually impossible (there were 4, I think, for 6, 12VDC and for 117VAC, plus one other alternative).
Cheers--and thanks for taking the time to reply.
Leslie
SIR Leslie. . . . .
I think that as I had mentioned back at that time of the computation of the filament current and B+ voltage needs, that this set
is a total “hog” as compared to your apparent prior dealings with ” battery powered ” sets.
Particularly, in that respect of your having done a wiring up of series connected 9 volt battery packs to acquire your B+ level
Mmmmm, now isn’t that ‘bout $20 at Dollar store zinc-carbon prices . . . , forbid Alkaline versions.
This set will be needing in the decades of milliamperes of B+ .PLUS you need those filament up to full 6.3 voltage supply temp, particularly for the local osc tube function.
One thing that you might try, if using all of the filaments wired in parallel for 6.3 V operation, is to unplug the AF output tube and that will relieve a bit of the highest B+ drain level.
Then have a good antenna connected and merely look at the tuning eye opening / closing when you are then tuning into and off of a station(s) to see if there seems to be good reception of multiple stations across the band.
73's de Edd
