hi guys. a few months ago i posted a subject, 'is the salvageable' about this same radio. i am now trying to repair it.
i have the schematic but it does not tell me a number of things that i think i need to know.
also, the actual radio(s) are different than the schematics in many items. (caps, resistors, etc.)

this is one of the philcos that used an auto radio, model 801, with a transformer added to supply power.
it was burned up fairly well. i happened to run across a philco mdl 802 made for mopar on ebay while looking for a thumbwheel radio. there was only 30 minutes left in the auction and i got it for 37.00.
it is virtually the same radio except of course no changes to work with 115 volt current. so my first question is:

Can i simply restore this 802 auto radio and add a transformer that supplys the correct power for the radio as it is? it calls for 6.3v @9amps. i have found a couple of new transformers that meet this. they are about 30.00.

If i can do this, it appears i CANNOT use the field coil speaker in the original radio. there would be no power to it? can i use a standard auto speaker?

Or, would it make more sense to convert it to the way philco did for use? i do not know if the transformer for the 801 is good.
i can post any pics you like if it helps.

thank you
bert

JMHO, but the quick and easy way is to supply 6 volts to it and run the vibrator high voltage supply. But that's not the way I would do it if it were mine, as you'd have a buzzy car radio in a piece of furniture. I'd want to give it a "real" AC radio power supply and eliminate the vibrator set up.

The only good way is with a separate power transformer like the big one you have. Don't plan on using a vibrator supply.

Does anyone have a diagram for that chairside set, or the floor model version? The original vibrator supply put out only 215 volts DC.

Edit: The Chairside version needed a higher voltage to supply the field coil. More transformer choices in later posts.

Don

Information for the A-801 Chairside and A-361console are in the Philco RMS Yearbook for 1942. I would be glad to scan the information for anyone. Just need your email address.

The original power transformer in the Philco chairside model A-801 was part No. 32-8231. From what I have observed very few of the original transformers survived. Philco did not list voltages in the manuals I have for the A-801 (Mopar radio) or the A-361 console (Ford radio).

My A-801 has a replacement Stancor #P-6013 power transformer mounted on the wood transformer block. Information gleaned from the internet says P-6013 has the following specs: Primary 115v, secondaries. 700v. c.t. @120 ma., 5v c.t. @ 3amp, 6.3v @4.7 amp.

There are differences in the A-801 from the Mopar 801/ (Philco C-1908) to drop the B+ voltage. In the A-801 the speaker field coil (1075 ohms) takes the place of the first B+ dropping resistor (1000 ohms) in the car version. That takes care of voltage for the output transformer (same in both versions), and the 7C5 output tube screens). The 2nd. B+ dropping resistor is changed to 6800 ohms from 1000 ohms for the rest of the sets B+ line. Unless I missed something, the rest of the radio is the same. Oh, yeah, there are some slight changes in the antenna input to account for the single wire that is stapled around the inside perimeter of the cabinet, posing as an antenna.

If there is any interest, I could pull the chassis and transformer from my set and measure the voltages. I need to clean those damn push-button switches again anyway.

Thanks! don and meade.
i will pm you meade. any info you can supply me would be great. i have a schematic for the chairside version but it does not list hardly any voltages. most of the wires from the transformer went directly to the 5y4g. i was able to label which wires from trans went to which pins during disassembly.

if there is interest i will keep a running post of this project.

thank you

Meade, I sent a PM with my e-mail address so I can see the schematics. Edcor has a larger version of the Stancor P6013, although I think this is more plate voltage than this set needs.

EDIT: Meade, Thanks for the clear schematic. It shows that AC sets were using the loktal socket 7Y4 rectifier, that may have led to shorts and fires as it is a version of the 6X5. Since the tubes are horizontal in this chairside set, a cheap rugged 6AX5GT rectifier in an octal socket would be much safer. (5Y4 tube should be vertical, OK for console sets)

Nostalgiaair has the C-1908 schematic for the auto radio version, no voltages there either. http://www.nostalgiaair.org/PagesByMode ... 013955.pdf
Don

Okay guys, I put my A-801 chairside radio on the bench for voltage measurements. First of all, I found one deviation from the A-801 schematic: B+ dropping resistor R-60 (27K) is actually 17K in my radio, and appears to be original. It has increased in value to 19K. Replacement power transformer is a Stancor P-6013.

All voltages taken with line voltage at 120 VAC, radio playing.

All filament voltages measured 6.3/6.6 VAC through-out the set. Voltage at junction of R-60, R-72: 243 vdc.

7Y4 rectifier:
Plates pins 3 & 6: 750 vac
Cathode pin 7: 424 vdc

7C5 output tubes:
Plate pin2: 327 vdc
SG pin 3: 339 vdc
Grid pin 6: 0 vdc
Cathode pin 7: 21 vdc

7A4 phase inverter:
Plate pin 2: 182 vdc
Grid pin 6: 26 vdc
Cathode pin 7: 161 vdc

7B6 det./ 1st. audio:
Plate pin 2: 128 vdc
Grid pin 3: 0
Cathode pins 4 & 7: 0 vdc (ground)
Diode pin 5: -3.85 vdc
Diode pin 6: -2.6 vdc

7A7 I.F.:
Plate pin 2: 336 vdc
2nd. Grid pin 3: 97 vdc
3rd. Grid pin 4: 0 vdc
Grid pin 6: 0 vdc
Cathode pin 7: 4.7 vdc

7B8 det./osc. :
Plate pin 2: 227 vdc
2nd. Grid pin 3: 112 vdc
Grid pin 4: -3.5 vdc
3rd. Grid pin 5: 97 vdc
4th. Grid pin 6: -1.98 vdc
Cathode pin 7: 2.02 vdc

7A7 RF:
Plate pin 2: 175 vdc
2nd. Grid pin 3: 98 vdc
3rd. Grid pin 4: 0 (ground)
Grid pin 6: -.7 vdc
Cathode pin 7: -2.04 vdc

Hope this helps; I wish Philco would have listed voltages for their sets.

Meade, It looks like there is plenty of voltage available for the original chairside field coil speaker. The screen voltage on the 7C5 is higher than the plate voltage, causing a high idle current. Most of the smaller tubes have quite high voltages, I think Philco needed one more dropping resistor between the output transformer and the 10 uF capacitor that feeds the 7C5 screen, which would bring everything else in line. For 327 volts on the plate, Screen could be dropped to 225 volts according to my CBS tube manual, but that might be too low for everything after it. Maybe 270 volts would be good.
Don

I think you’re right; in fact the Mopar 801/ Philco C1908 does exactly that. It has a 1K resistor between the output transformer c/t and the 7C5 screens. I marked some voltages on the schematic for an almost identical Mopar 802/ C-4608 some time ago. I noted that the 7C5 plates had 214 vdc, while the screens were at 200 vdc.

Meade, 214 volts on the plates of the 7C5 sounds much safer than 324. It is interesting that your Stancor is rated 700 volts but putting out 750 volts due to the light load and today's higher line voltages. I was thinking Bert's set could benefit from a lower voltage transformer, to reduce the stress on the tubes, field coil, and capacitors. The Stancor P6013 was not the original from Philco?
How about an Edcor XPWR044-120 with 560 volts CT @150 mA, 6.3 volts @5.5 A, and a second 6.3 volts @ 2 A which could power a 6AX5 or the original 7Y4 rectifier. Putting the rectifier on a separate winding avoids the hazard of a heater to cathode short as well. This would bring the plate voltage down 90 volts, as the lower current will cause a lower drop across the field coil, so the 7C5 will get 235 volts on the plates and the smaller tubes will be closer to the normal values, even if the original resistor values are left in.

Edit: Meade's careful measurements show that the 7A7 IF tube has 336 volts on the plate, as it is fed from the same spot as the 7C5 Screen, both are way too high. The 7A7 RF tube is fed from the other side of R72 so it has 175 volts, more than it needs. A lower voltage from the transformer would help all this.

Don

hi meade and don. i wont be home until tomorrow but got online for a minute. my chairside had a 5y4g in it. the schematic i have shows that to be the correct tube. i also found info that there were several runs each with multiple changes to caps, resistors, etc. i have not been on my email to see the schematic you sent meade. i will look tomorrow. seems the consensus is to change over the 802 model to work with a 115v transformer.
ill get to it tomorrow when i return.
bert

Bert, I did not send any schematics, but used the ones sent by Meade and the ones on Nostalgiaair.
It is a disgrace that Philco did not put any voltage readings on the schematic, as Meade's careful measurements show that his radio is running at quite high voltages. It may be that Philco used whatever transformers were available due to wartime shortages. The fact that your original chassis burned up leads me to recommend a different power transformer to get the replacement auto radio running closer to the original 215 to 250 volts DC at the output transformer, used in all vibrator-powered auto radios. That would cause all the other voltages and idle current to fall into place.
I also recommend the 6AX5GT rectifier, it can run in any position, as the 5Y4 can short out if operated horizontally and the filament sags, "unless pins 2 & 7 are in a horizontal plane" says the manual.
The power transformer has to put out enough voltage to power the field coil first, then the rest of the radio gets what is left, as shown in the A801 diagram. I cleaned up my earlier posts, I hope that helps.
Don

im home...........
MEADE, thank you so much for for your time and effort. i know this took some work. i am amazed that you are reading 700+ volts.
DON....thank you for your input as well.
i am going to recap the 802 as is first and then attempt to change it over to 115v power. i will need more help when i start to change it from 'auto to home' radio. if the radios were identical i would do better, but there are too many differences for my untrained mind to grasp all at once.
also.......i think i made a mistake about the 7y4 and 5y4 , i have a philco chairside 38-7 i am working on also and i believe i mixed the two radios up. .

i am exited and apprehensive both at once. i really want to fix this radio and cabinet. if i can make it work correctly i am going to 'loan' it to my buddys father who is 90 and had one in his home as a young man. my buddy said he'll give it back to me at the appropriate time.

bert

Don and Bert,
The original power transformer for the A-801 Chairside radio was Philco # 32-8231. I found my Philco parts catalog for 1956 and it does list that transformer. The specs for the original 32-8231 transformer are: Horizontal mounting, 3” H, 3 ¼” L, 2 ½” W. List price $13.00 in 1956
Primary:115 vac-60 cycles.
Secondary: 550 vac (c.t.) at 75ma., 6.4 vac at 4.3 amps.

Better than Stancor P-6013 (750vac) the unknown tech chose to replace the transformer in my radio, but still too high. For comparison, the Philco # 65-0347 vibrator power transformer secondary for the Mopar 801 and 802 is rated at 225vac (450 c.t.) at 60 ma. No rating for filaments of course, because the filaments, dial lamp, and the speaker field coil were fed directly from the 6vdc power input line.

Here is the Mopar 802 schematic with voltages:

https://sites.google.com/site/philcoa801chairside/

one of my favorite radios!

I think that other than the power supply differences, the radio had a few other differences than the auto version that it was built from. I was thinking it had an extra power output tube, but I could be wrong. I would recommend simply getting a new power trans made by stancor or someone, as the orginal one was way too small anyways. Mine still works, but runs HOT.

Remember, the higher voltage from the Philco 32-8231 is needed to power the Field Coil speaker. The Edcor XPWR044-120 transformer I suggested Saturday has the right voltage after all, and a higher current rating so it won't get too hot. It is a bit larger as a result, but it looks like there is plenty of room in the cabinet.
Don

thanks don. my radio does have the original philco 32-8231 transformer. i will look up the Edcor XPWR044-120 and find who to order one from.

bert

Bert, You're welcome. You order the Edcor transformer direct from the factory and they build it for you, here http://www.edcorusa.com/products/637-xpwr044_120.aspx
The Speakerdude posted a link showing this nice cabinet, and the area around the transformer looks crowded. Edcor shows the dimensions so you can be sure it will fit http://www.edcorusa.com/DWG/15000-EI125-150-0X.pdf

They have an announcement that they will shut down for the holidays, so you should order by Nov. 11 for delivery before the end of the year http://www.edcorusa.com/news/12-happy-holidays.aspx

The 5-10-10-20 twist-lock electrolytic can be replaced with a 20-20-20-20 @ 475 volts, C-EC-20X4-475 from AES. That is 2" high, other choices are taller, measure to see if they will fit under the cover. In any case, only connect 20 uF to the rectifier cathode, you can connect larger values after the field coil.

A less expensive choice is a JJ 40-20-20-20 @ 500 volts, C-EC40-20X3-500 from AES. You need to buy the capacitor mounting clamp. I used one of those capacitors, but had to make a larger mounting hole, the terminals are too far apart to fit in the original hole. It's more work and won't look original.

Other people may suggest different electrolytics, or re-stuffing the old one.

I am just a hobbyist, not connected with any vendor.
Don

Thanks don. thank you too meade. i have swapped out (bad volume/tone pot, color wheel, push buttons) and repaired the 802 and it is working correctly as it should in the 'automobile' configuration. it actually places very well thru a 6 volt auto battery with a 12" PM speaker and picks up all local stations. there is almost no hum at all.

NOW!......i need help in what to remove, as in the vibrator, etc, and exactly how to wire in the edcor transformer. pls keep in mind i have not done this very long. my schematic reading is good but not like you guys. im just unsure and dont want to damage a perfectly good working radio at this point.

my voltages running on the vibrator are almost exactly where they should be.
thank you
bert