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Unidentified Grundig mono console questions

Oh... I added some pics:

http://s720.photobucket.com/albums/ww209/PatriceBrousseau/Fleetwood - Grundig/

When I received the receiver, only the woofer was connected. The red shielded wire was wrapped with the shielded end and stayed right beside the chassis on the internal shelf supporting the amp. The mid had a side disconnected and was, obviously, not working. Tested it and it worked fine...

I know I have to finish the recap job first but I try to figure how to connect properly the speakers and why the supposed voltage isn't there.

Thanks.

Patrice
 
I also saw a 3.04k 1/2w resistor tied to the .01uf cap (C602) on one end and to the yellow wire coming from the OPT on the other end. No 3.04k on the schematic so there are differences between schematic and the real gear...
 
"Do you think someone messed up the connections?"
Yep. Not liking what I'm seeing but I think we can get it sorted out.
First, it looks like the lower P/P EL84 in the 2nd pic may be out of circuit since I cannot see a transformer connection to anode/plate #7 or a screen connection to #9. May have been converted to single-ended with a replacement transformer on the upper P/P EL84 only and no taps or extra windings. Transformers destruct from being run with defective capacitors in the radio and this one's full of aged caps needing replacement. The tweeter ckt is presently totally nonop but the wire for it may still have high voltage on them. We are probably going to make it work single-ended as-is if the transformer is good for now to do diagnosis and overhaul. It'll need at least another push-pull transformer to restore both tubes into circuit, the ultraLinear screen-grid winding feature is probably out of reach for resto as is also the tapped output set-up. We would need a similar parts junker with a good OPT, not a likely find. All of the brown ERO capacitors have to be replaced. It looks like capacitor C501 has been replaced with a pair of clear polystyrene no-leakage plastic film caps, they are probably fine and replaced the defective one that may have ruined the original OPT. The 2 resistors from one end of them look wrong, that end of the 700k resistor should go to ground/chassis. Check diagram and chassis.
For single-ended operation, C501 can be either value and at least 600V and must go from plate of functional tube to HV blue wire from other end of transformer primary.
Low voltages probably due to leaky capacitors and/or tired EZ81 rectifier tube.
The orange wire from the OPT could be a secondary tap, confirm with continuity check to the speaker connections.
Still studying, more in edits to this post & additional posts, so refresh page occasionally.
 
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The white wire on the second EL84 on this page is coming from the OPT.

Or do you mean on the picture where there's an ERO cap in bad shape tied to pin7?
 
Oh, you're right: 266v on the EL84 with the white wire on pin7.

Nothing on the other (around 2v) pin7.

Like I said, there's a bunch of snipped wires coming from the OPT, four in fact. Colors are yellow - green -red - blue.
 
OK, may be the original xformer. So why the butchery if so. Hmmmm---. Can you get close-up pic of OPT with snipped wires?
Refresh page and reread long post for any updates to now. I'll carry forward in new post.
 
Ok, pics of the OPT and underside snipped wires:

IMGP1427.jpg


IMGP1423.jpg


For what it's worth:

Resistance readings between the now connected blue (tied to 50uf cap) and white (tied to plate): 470 ohms

Resistance readings between the snipped wires (there was a black one also, not seen first because it was hidden by tape):

- red and blue: 658 ohms
- black and yellow: 24 ohms
- black and green: 24 ohms

**EDIT: no resistance readings between what's now connected (blue and white) and the five snipped ones.

Thanks.

Patrice
 
Patrice, I think that's the original OPT after all. The schem doesn't give winding color codes. I'm trying to work it out here but continuity/resistance checks will help if not open.
Thank you! See next post.
 
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Thnx!! Definitely original OPT, now we are getting somewhere.
Red probably went to other EL84 plate and the free blue to HV with the 1st blue. Please see if white wire appears to have been resoldered since mfgred.
Black went to 227V line & fed output tube screens thru green and yellow wires, polarity unknown at present.
Checking color codes on other Grundig OPTs without screen windings now.
 
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Yes, OPT original. BV 1013/1 and same on schematic.

Connections as now:

Top of the tranny:

- medium-sized orange goes to terminal strip but connected to nothing...
- medium-sized blue goes to external speaker plug, this one tied to a .4uf, probably C503 (near volume pot on the underside)
- big yellow tied to 200 ohms, probably R503. It is also grounded to chassis via terminal strip

Bottom of tranny:

- big green goes directly to speaker (yellow wire)
- tiny white goes to plate of the now working EL84
- tiny blue goes to 50uf cap, probably C804

Thanks for your invaluable help.

Patrice
 
Pio1980 said:
Thnx!! Definitely original OPT, now we are getting somewhere.
Red probably went to other EL84 plate and the free blue to HV with the 1st blue. Please see if white wire appears to have been resoldered since mfgred.
Black went to 227V line & fed output tube screens thru green and yellow wires, polarity unknown at present.
Click to expand...

There's trace of past soldering on pin 3 (grid) of the non-operative EL84 for sure. Something was there.
 
Pio1980 said:
Thnx!! Definitely original OPT, now we are getting somewhere.
Red probably went to other EL84 plate and the free blue to HV with the 1st blue. Please see if white wire appears to have been resoldered since mfgred.
Black went to 227V line & fed output tube screens thru green and yellow wires, polarity unknown at present.
Checking color codes on other Grundig OPTs without screen windings now.
Click to expand...

227v line. You mean I should solder it to the second 50uf cap?
 
Hmmm... There's also an added 100uf@25v Aerovox cap tied to screen of working EL84 and on the other end, to the DIN tape connector at the back...:scratch2:
 
Have to leave, be back later.
I need to know if the white wire has been resoldered to determine if that's the original connection or possibility it's been moved.
Check schematic for correct connections around 700K resistor in question, be back later.
 
"Hmmm... There's also an added 100uf@25v Aerovox cap tied to screen of working EL84 and on the other end, to the DIN tape connector at the back.."
That was a necessary part of the single-ended conversion, it's a signal shunt across the 200^ cathode bias resistor. That's to the supressor which is internally connected to the cathode, not the screen grid which is position #9. I think the grounded end of the 200^ resistor was originally soldered to the orange wire tie point and there was no shunt capacitor.

" At the end of the aforementioned 700k, there's a trace of a snipped connection. What was there?"
Most likelty the clipped stub of the old capacitor. That end of the 700k resistor must go to ground/chassis for proper operation.

"- medium-sized orange goes to terminal strip but connected to nothing..."
"Following, a pic of an unused orange wire coming form the OPT. I don't know what's the purpose (maybe to connect to the mid?). "
Quite possibly, or the woofer. The schem doesn't differentiate which is which.

We still need to figure out why the output ckt was changed. The possibilities are bad OPT winding, couldn't get another EL84, someone before couldn't understand how original ckt worked and changed it to something simpler, dunno.
Yes we can probably change it back but we don't know the color code for polarity of the OPT or why it was changed. Needs thinking out.
 
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Pio1980 said:
" At the end of the aforementioned 700k, there's a trace of a snipped connection. What was there?"
Most likelty the clipped stub of the old capacitor. That end of the 700k resistor must go to ground/chassis for proper operation.
Click to expand...

Hard to see by the pics but the end of this resistor is tied to a socket lug going to chassis.

Pio1980 said:
We still need to figure out why the output ckt was changed. The possibilities are bad OPT winding, couldn't get another EL84, someone before couldn't understand how original ckt worked and changed it to something simpler, dunno.
Yes we can probably change it back but we don't know the color code for polarity of the OPT or why it was changed. Needs thinking out.
Click to expand...

Was asking myself the same question yesterday. There was a purpose to operate this change and I hope that wasn't bad OPT winding. The only way to be sure is I guess, to reconnect all stuff like it was initially. No wonder that the stronger testing 6BQ5 is located on the side where it is out of circuit...

Thanks.

Patrice
 
Pio1980 said:
Have to leave, be back later.
I need to know if the white wire has been resoldered to determine if that's the original connection or possibility it's been moved.
Check schematic for correct connections around 700K resistor in question, be back later.
Click to expand...

I'll try to look (at the end of day, after work) if the solder connections (white wire) appears original or not. If it's not the original location, where was it before?:sigh:
 
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