Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

High voltage readings
#1

I'm wrapping up repairs to a model 91 with a 225 chassis. There is a problem with plate voltages for the RF(44), detector oscillator(36) and the IF (44) tubes. The voltages are 265 to 272 volts, which exceeds the maximum plate voltage shown in the tube manuals. Measurements taken were at 115 volts on the line, plugged directly into a wall receptacle at 124 or 125 volts drives the plates up to 285 to 290 volts.Needless to say, the radio is very loud when the volume is turned up. Other than these voltages, the radio is working well.

Output of the power supply is 332 volts at the input to the filtering section and 286 at the output of the filter.

I have several solutions for lowering the voltage but I'd rather not put in parts that weren't in the original design if I can help it.

Any suggestions would be appreciated.

Thanks

Tom

Sometimes I wonder whether the world is being run by smart people who are putting us on or by imbeciles who really mean it.


Messages In This Thread
High voltage readings - by Tom45acp - 05-08-2020, 05:37 PM
RE: High voltage readings - by gregb - 05-08-2020, 05:50 PM
RE: High voltage readings - by Tom45acp - 05-08-2020, 07:17 PM
RE: High voltage readings - by Radioroslyn - 05-08-2020, 08:44 PM
RE: High voltage readings - by Tom45acp - 05-09-2020, 04:00 PM
RE: High voltage readings - by Steve Davis - 05-09-2020, 05:57 PM
RE: High voltage readings - by morzh - 05-09-2020, 06:31 PM
RE: High voltage readings - by Tom45acp - 05-10-2020, 08:29 PM
RE: High voltage readings - by morzh - 05-10-2020, 09:01 PM
RE: High voltage readings - by Tom45acp - 05-11-2020, 08:59 AM
RE: High voltage readings - by morzh - 05-11-2020, 10:42 AM
RE: High voltage readings - by Tom45acp - 05-11-2020, 06:44 PM
RE: High voltage readings - by morzh - 05-11-2020, 08:45 PM
RE: High voltage readings - by Tom45acp - 05-12-2020, 08:44 AM
RE: High voltage readings - by RodB - 05-12-2020, 09:19 AM
RE: High voltage readings - by morzh - 05-12-2020, 10:18 AM
RE: High voltage readings - by Tom45acp - 05-12-2020, 12:12 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Zenith H725
hello Ed, how about that speacial tape used for ducting it's like foil or how about thin piece of aluminum roof flash...radiorich — 12:19 AM
Zenith H725
Ed; One material that I have seen, but never tried for this was material for making exhaust gaskets, it's similar to ...Arran — 11:42 PM
Zenith H725
I just remembered, I have some hi temp silicone rubber material which could do the trick. Or a piece of FR4 laminate. Th...EdHolland — 08:39 PM
Zenith H725
The PSU filter cap arrived today (thank you USPS!) so I will work on that later. Meanwhile, I have the dial, speaker...EdHolland — 06:42 PM
Philco 610B oscillator wiring
Thanks Terry. After checking my notes I think I recorded about -10v at the 6A7 G4/control grid. The screen grid (G3 &...Tubester — 05:59 PM
The list of my radio & TV collection!
Magical chords of forgotten melodies, old nostalgic music on an old radio... Saturday night blues on the Mid-Waves on an...RadioSvit — 12:20 PM
Philco 42-345 Restoration/Repair
Thank you MrFixr55 the issue with this radio is that the internal coil antenna is missing and there was a wire in its pl...osanders0311 — 11:34 AM
Philco 610B oscillator wiring
Regarding the oscillator circuit which is comprised of the 6A7's cathode, control grid, and screen grid. These elements ...Radioroslyn — 10:33 AM
Philco 42-345 Restoration/Repair
Hi OSanders, First off, welcome to the Philco Phorum where Phine Phamily-Phriendly Pholks Phull of Philco Phacts and P...MrFixr55 — 08:41 AM
Philco 42-345 Restoration/Repair
Today I've been reading through the site trying to learn more about this radio. I also soldered the lose power cord cabl...osanders0311 — 08:24 PM

[-]
Who's Online
There are currently 2420 online users. [Complete List]
» 1 Member(s) | 2419 Guest(s)
Avatar

>