Philips B3X85U troubleshooting - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Steve_P · 17th Jan 2011, 11:28 pm

Fine. Not a problem there. What do you get at the other side of it?

Cheers,

Steve P.

Abraham · 17th Jan 2011, 11:48 pm

It measures 00.0 also

Steve_P · 17th Jan 2011, 11:53 pm

Right. There should be a voltage here. The next valve back is a UABC80.

http://www.r-type.org/exhib/aaa0171.htm

There should be a voltage on Pin 9. I suspect there isn't. There is a resistor between here and the HT line. If there is voltage on the other end of this resistor, then check the wiring and then change this resistor.

Cheers,

Steve P.

Abraham · 17th Jan 2011, 11:56 pm

should I re-solder the capacitor before taking the reading?

Steve_P · 17th Jan 2011, 11:57 pm

Yeah, you might as well.

Cheers,

Steve P.

Abraham · 18th Jan 2011, 12:23 am

Don't know if I mistakenly disconnected the wrong capacitor. It was connected to Pin #2 of the UBC81

Abraham · 18th Jan 2011, 12:32 am

The valves on the radio are: B1- UCH81, B2 - UF89, B3 - UBC81, B4 UL84, B5 - UY41, B6 - UM80

Steve_P · 18th Jan 2011, 12:33 am

Yes. By the way it does not have a UABC80. My mistake. It has a UBC81 instead.

http://www.r-type.org/exhib/aaa0478.htm

The capacitor you want goes between Pin 1 of this valve and Pin 2 of the UL84. There should be nothing on Pin 2 of the UL84. The other side of this capacitor should go to Pin 1 of the UBC81. There should be a voltage here, if not the same applies, trace it back to the HT line.

The cap on Pin 2 of the UCL81 is the wrong on.

Cheers,

Steve P.

Abraham · 18th Jan 2011, 12:36 am

Here's a pic of the capacitor I disconnected.

Abraham · 18th Jan 2011, 1:02 am

Also what does HT stand for

AlanBeckett · 18th Jan 2011, 1:11 am

Literally High Tension.
B+ in American.
Alan

Abraham · 18th Jan 2011, 1:14 am

On the cap, which I disconnected and goes from Pin #2 of the UBC81 to Pin #1 of the UL84 by means of a jumper wire and resistor. On the side that it is supposed to go to Pin #1 of the UBC81, it does not have a reading. Nor does the side that has the jumper wire that connects to the resistor, does not give any reading at all. (no voltage).

Station X · 18th Jan 2011, 1:17 am

HT stands for High Tension meaning high voltage.

It's difficult to tell from the picture which capacitor you've disconnected. Reconnect it and then recheck the voltage between Chassis and pin #2 of the UL84. In post #15 you said it read +4.4V which indicates a fault condition. If you still have a positive voltage on pin #2 of the UL84 disconnect the capacitor from pin #2 and check the voltage there again. If it's now zero this indicates that the capacitor is faulty.

Report your findings.

EDIT. We posted together. You've disconnected the wrong capacitor. Reconnect it and test as above.

Abraham · 19th Jan 2011, 12:22 am

The cap that I had disconnected was the one that goes to Pin #1 of UBC81 and disconnected it measures 0.0 On the side of the cap that goes to Pin #2 of the UL84, it measures 2.2.

Other than that, on the UL84, measurements of
Pin #2 is 0.25mv DCV (Control Grid)
Pin #9 is 99V DCV (Screen Grid)
Pin #7 is 115v DCV (Anode)
Pin #3 is 5.23v DCV (Cathode)
Pin #5 is 94.5V ACV
Pin #4 is 49.0 ACV

On the UBC81, measurements are
Pin #1 - 0.63mv DCV (Anode)
Pin #2 - 0.82v DCV (Control grid)

All this was done with the cap disconnected from Pin #1 of the UBC81
Thanks again

Steve_P · 19th Jan 2011, 12:30 am

There should be more than that on Pin 1 of the UBC81. Check this again and check the resistor that should go between here and the HT line. Check the wiring and if there is voltage on the other side of this resistor, change it.

If not, go back until you do find HT.

Cheers,

Steve P.

Station X · 19th Jan 2011, 2:07 am

Quote:

On the side of the cap that goes to Pin #2 of the UL84, it measures 2.2.

Other than that, on the UL84, measurements of
Pin #2 is 0.25mv DCV

If both measurements were taken with the cap disconected from pin #2 of the UL84, then the capacitor is faulty.

Abraham · 19th Jan 2011, 4:46 am

I checked again now with the cap soldered on to Pin #1 and it fluctuates from 4.5 to 5.0mv on Pin #1.

can I replace the cap with the same 10Nf but instead of a 1000vcc, it is 250v?

Station X · 19th Jan 2011, 12:01 pm

Let's do this one step at a time.

Before you replace the capacitor you need to find out why you don't have HT voltage on pin #1 of the UBC1.

Follow Steve's instructions in post #35.

Hunts smoothing bomb · 19th Jan 2011, 12:34 pm

Hi all,

I don't know this set but does anyone know if it has a mains transformer? If not is the HT about right as the mains voltage supply in Panama City according to this link http://www.kropla.com/electric2.htm is 120vac 60Hz.

In an earlier post a resistance value of 1748 ohms was quoted but I couldn't make out where exactly it was measured from, could you be more specific Abraham as to where your probes were when you took this reading?

Cheers
Lee

Station X · 19th Jan 2011, 12:53 pm

Here's an extract from the service manual.

THAT capacitor is C29. It doesn't go directly to UL84 pin #2, but goes via resistor R21.

-------------------------------------------------------

The most likely cause for no HT on the UBC81 is R15 being high value or open circuit.

With no power applied check its value with you meter on ohms range. Replace if more than 20% off value.

With power applied measure the voltage from chassis to both sides of R15.

Report back here. There are several of us here keen to see this radio working.

17th Jan 2011, 11:28 pm	#21
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Philips B3X85U troubleshooting Fine. Not a problem there. What do you get at the other side of it? Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

17th Jan 2011, 11:48 pm	#22
Abraham Retired Dormant Member Join Date: Dec 2010 Location: Panama City, Panama Posts: 60	Re: Philips B3X85U troubleshooting It measures 00.0 also

17th Jan 2011, 11:53 pm	#23
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Philips B3X85U troubleshooting Right. There should be a voltage here. The next valve back is a UABC80. http://www.r-type.org/exhib/aaa0171.htm There should be a voltage on Pin 9. I suspect there isn't. There is a resistor between here and the HT line. If there is voltage on the other end of this resistor, then check the wiring and then change this resistor. Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

17th Jan 2011, 11:56 pm	#24
Abraham Retired Dormant Member Join Date: Dec 2010 Location: Panama City, Panama Posts: 60	Re: Philips B3X85U troubleshooting should I re-solder the capacitor before taking the reading?

17th Jan 2011, 11:57 pm	#25
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Philips B3X85U troubleshooting Yeah, you might as well. Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

18th Jan 2011, 12:23 am	#26
Abraham Retired Dormant Member Join Date: Dec 2010 Location: Panama City, Panama Posts: 60	Re: Philips B3X85U troubleshooting Don't know if I mistakenly disconnected the wrong capacitor. It was connected to Pin #2 of the UBC81

18th Jan 2011, 12:32 am	#27
Abraham Retired Dormant Member Join Date: Dec 2010 Location: Panama City, Panama Posts: 60	Re: Philips B3X85U troubleshooting The valves on the radio are: B1- UCH81, B2 - UF89, B3 - UBC81, B4 UL84, B5 - UY41, B6 - UM80

18th Jan 2011, 12:33 am	#28
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Philips B3X85U troubleshooting Yes. By the way it does not have a UABC80. My mistake. It has a UBC81 instead. http://www.r-type.org/exhib/aaa0478.htm The capacitor you want goes between Pin 1 of this valve and Pin 2 of the UL84. There should be nothing on Pin 2 of the UL84. The other side of this capacitor should go to Pin 1 of the UBC81. There should be a voltage here, if not the same applies, trace it back to the HT line. The cap on Pin 2 of the UCL81 is the wrong on. Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

18th Jan 2011, 12:36 am	#29
Abraham Retired Dormant Member Join Date: Dec 2010 Location: Panama City, Panama Posts: 60	Re: Philips B3X85U troubleshooting Here's a pic of the capacitor I disconnected. Attached Thumbnails

18th Jan 2011, 1:02 am	#30
Abraham Retired Dormant Member Join Date: Dec 2010 Location: Panama City, Panama Posts: 60	Re: Philips B3X85U troubleshooting Also what does HT stand for

18th Jan 2011, 1:11 am	#31
AlanBeckett Rest in Peace Join Date: Dec 2008 Location: Burton upon Trent, East Staffordshire, UK. Posts: 1,686	Re: Philips B3X85U troubleshooting Literally High Tension. B+ in American. Alan

18th Jan 2011, 1:14 am	#32
Abraham Retired Dormant Member Join Date: Dec 2010 Location: Panama City, Panama Posts: 60	Re: Philips B3X85U troubleshooting On the cap, which I disconnected and goes from Pin #2 of the UBC81 to Pin #1 of the UL84 by means of a jumper wire and resistor. On the side that it is supposed to go to Pin #1 of the UBC81, it does not have a reading. Nor does the side that has the jumper wire that connects to the resistor, does not give any reading at all. (no voltage).

18th Jan 2011, 1:17 am	#33
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,287	Re: Philips B3X85U troubleshooting HT stands for High Tension meaning high voltage. It's difficult to tell from the picture which capacitor you've disconnected. Reconnect it and then recheck the voltage between Chassis and pin #2 of the UL84. In post #15 you said it read +4.4V which indicates a fault condition. If you still have a positive voltage on pin #2 of the UL84 disconnect the capacitor from pin #2 and check the voltage there again. If it's now zero this indicates that the capacitor is faulty. Report your findings. EDIT. We posted together. You've disconnected the wrong capacitor. Reconnect it and test as above. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

19th Jan 2011, 12:22 am	#34
Abraham Retired Dormant Member Join Date: Dec 2010 Location: Panama City, Panama Posts: 60	Re: Philips B3X85U troubleshooting The cap that I had disconnected was the one that goes to Pin #1 of UBC81 and disconnected it measures 0.0 On the side of the cap that goes to Pin #2 of the UL84, it measures 2.2. Other than that, on the UL84, measurements of Pin #2 is 0.25mv DCV (Control Grid) Pin #9 is 99V DCV (Screen Grid) Pin #7 is 115v DCV (Anode) Pin #3 is 5.23v DCV (Cathode) Pin #5 is 94.5V ACV Pin #4 is 49.0 ACV On the UBC81, measurements are Pin #1 - 0.63mv DCV (Anode) Pin #2 - 0.82v DCV (Control grid) All this was done with the cap disconnected from Pin #1 of the UBC81 Thanks again

19th Jan 2011, 12:30 am	#35
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Philips B3X85U troubleshooting There should be more than that on Pin 1 of the UBC81. Check this again and check the resistor that should go between here and the HT line. Check the wiring and if there is voltage on the other side of this resistor, change it. If not, go back until you do find HT. Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

19th Jan 2011, 4:46 am	#37
Abraham Retired Dormant Member Join Date: Dec 2010 Location: Panama City, Panama Posts: 60	Re: Philips B3X85U troubleshooting I checked again now with the cap soldered on to Pin #1 and it fluctuates from 4.5 to 5.0mv on Pin #1. can I replace the cap with the same 10Nf but instead of a 1000vcc, it is 250v?

19th Jan 2011, 12:01 pm	#38
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,287	Re: Philips B3X85U troubleshooting Let's do this one step at a time. Before you replace the capacitor you need to find out why you don't have HT voltage on pin #1 of the UBC1. Follow Steve's instructions in post #35. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

19th Jan 2011, 12:34 pm	#39
Hunts smoothing bomb Octode Join Date: Oct 2005 Location: Wimborne, Dorset, UK. Posts: 1,407	Re: Philips B3X85U troubleshooting Hi all, I don't know this set but does anyone know if it has a mains transformer? If not is the HT about right as the mains voltage supply in Panama City according to this link http://www.kropla.com/electric2.htm is 120vac 60Hz. In an earlier post a resistance value of 1748 ohms was quoted but I couldn't make out where exactly it was measured from, could you be more specific Abraham as to where your probes were when you took this reading? Cheers Lee __________________ Lee

19th Jan 2011, 12:53 pm	#40
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,287	Re: Philips B3X85U troubleshooting Here's an extract from the service manual. THAT capacitor is C29. It doesn't go directly to UL84 pin #2, but goes via resistor R21. ------------------------------------------------------- The most likely cause for no HT on the UBC81 is R15 being high value or open circuit. With no power applied check its value with you meter on ohms range. Replace if more than 20% off value. With power applied measure the voltage from chassis to both sides of R15. Report back here. There are several of us here keen to see this radio working. Attached Thumbnails __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.