[Radio Hound]

I may be overlooking it but I can't find out what the pin voltages, on the 80 tube, should be on the Philco model 610 . If anyone has this information. I would appreciate it.

[rck46]

Plate and filament voltages are listed on the table for transformer voltages on Riders pg 6-19. see http://www.nostalgiaair.org/pagesbymodel...013797.pdf

[Radioroslyn]

1or4 to the chassis 255vdc 3-4 680vac.

[Radio Hound]

Do you have any idea why I would be getting 395v on pin 1 or 4 to chassis on the 80 tube?

1or4 to the chassis 255vdc 3-4 680vac.

[morzh]

Do you have the speaker connected?

[Radioroslyn]

If the spkr is wired in make sure the field coil isn't open.

[Radio Hound]

yes

Do you have the speaker connected?

[Radio Hound]

Will check today. I did check in the beginning but I did have to rewire it so maybe I did it wrong. I will re check my wiring too.

If the spkr is wired in make sure the field coil isn't open.

[Radioroslyn]

Sounds like your p/s is running without a load across it. Measure the voltage across the second filter cap and that at pin 2 of the 42 tube. Methink some where the voltage is going to be very low.

[Radio Hound]

Terry,
Thanks for helping me and plz understand I am still very new at this. I went out today and rechecked the speaker, the field coil and my rewiring. All seems good and correct. I think I understand the schematics really well but I struggle with trouble shooting and terminology. When you say to measure across the second filter cap do you mean from one end of the cap to the other or take measurements at each end to the chassis. Don't laugh or say rookie lol. End to end is -400v. Measuring at each end to chassis is 355v at pos end and -24v at neg end. Also You are talking about number 55 8mf filter cap aren't you.

Also I will list the pin voltages for the 80, 6A7 and the 42. The 80 tube voltages are pin 1 to chassis 385v, pin 4 to chassis 381v, pin 3-4 725 vac. The 6a7 pin 1 - 7.3v, pin 2 - 225v, pin 3 - 57v, pin 4 - 103v, pin 5 - -123v, pin 6 - .016v, pin 7 - .012. The 42 tube pin 1 - 7.2v, pin 2 - 355v, pin 3 - 354v, pin 4 - -24v, pin 5 - .3v, pin 6 - .010v.

I also read a thread on another 610 that had similar voltages on the 6a7 and he had a problem with the 32k resistor. Just to let you know I did recap and change out all resistors. I went back and checked the resistor values in the set and the only one that is not real close is the 3/4 meg that connects to part 57 (which ohmed out good too). It is reading 710K instead of 750k.

[morzh]

Dumb question, have you checked your tubes, especially the 42?

And, when showing voltages on the filament pins, like pins 1 and 6 of the 42, you mean the AC volts? In other words, you see all the tubes glow?

[Radio Hound]

All tubes tested good except the 42. It tested somewhat weak. Could that be my problem??? It was still in the green but barely. They all glow and yes I meant ac volts on those pins. Sorry for not saying.

[morzh]

If it is functional it is fine then, weak or not. Unless dead.

Here's how it is:

The unusually high voltage across the first filter cap #56 can be due to mostly the lack of load.

This could happen if your field coil is open, or if the resistor 57 is open.

But all your tubes have plate voltage relative to the Chassis which means neither of the above are the case.

So, also if the tubes do not draw current at all or very little. But if all tubes glow and all test OK (even if a bit weak) again, this is likely not the case.

See if there are oxidized pins on tubes or sockets, especially on the 42. It takes for the 42 to complete the circuit meaning that the Cathode and Anode have to make contact.

[Mondial]

You might check the wirewound bias resistor marked 57 on the schematic. See if it is high in resistance.

Something is funny with your voltage readings. The bias voltage on the 42 grid is -24 volts, which would indicate that almost 100 mA is flowing through R57, which should be about 260 ohms total. Yet your B+ voltage is high and the 42 is conducting very little current, as the plate and screen voltages are almost equal (pin 3 and pin 2)l. Typically the plate will be about 10 to 15 V lower because of the voltage drop in the output transformer primary winding when passing the normal plate current.

[Radio Hound]

I will get back with this on Monday. I'm on a 4 day work week with 16 to 18 hrs each day so I can't continue right now. I really appreciate the input and will clean my pins because this was a rust bucket. I will also try to find another 42 tube just to test. Part 57 ohms out perfect though so I don't think that is the problem but from what I get so far. It could be part 57 (Which I suspected first) , the field coil or the 42 tube. These are my prime suspects from what you all are saying. I will recheck these on Monday in depth and then let you know. Thank you so much for the help so far. You guys are great. I look forward to the day I can help someone.
thx, John