Murphy 405 line generator HELP!!! - UK Vintage Radio Repair and Restoration Discussion Forum

Courtney Louise · 24th Mar 2006, 6:04 pm

Hi guys,

I just got this off fleabay and its a bit dead...

I opened the PSU and found that the Mains transformer over many many hours ofrunning has decided t leak all of its wax and so has the smoothing choke.

Is there any way of fixing this. I have no clue to the voltages its supposed to give nor the currents.

Pics of the affected transformer enclosed...

Andi

tvden · 24th Mar 2006, 6:46 pm

Hi well I would say your transformer looks cooked, have you a model number for this item? as one of us may have a circuit regards Den

Nickthedentist · 24th Mar 2006, 6:50 pm

What a mess

However, if the transformer is still OK electrically, all might not be lost. "Migration" of wax and pitch from transformers doesn't necessarily mean they won't work, although obviously it's a sign that they've run far too hot.

Removal of the excess wax (hairdryer and plenty of old rags), then eliminating the cause of the hot running (e.g. shorted supply line, leaky coupling caps) has worked for me on several occasions (e.g. my Hacker Mayflower I radio).

Nick.

Courtney Louise · 24th Mar 2006, 7:04 pm

Hmmm model number ...

Well its a Pattern Generator type II by Murphy. and the PSU is Type A

Andi

Courtney Louise · 24th Mar 2006, 7:06 pm

I must admit to having not tried powering it up as I know some of the caps need changing and if its gotten that hot (looks like its been a long tim in happening tho) then I am guessing its shorted someplace...

There is also a 2A fuse missing..

Andi

Nickthedentist · 24th Mar 2006, 7:07 pm

Quote:

Originally Posted by Jarl Ayari

I must admit to having not tried powering it up as I know some of the caps need changing and if its gotten that hot (looks like its been a long tim in happening tho) then I am guessing its shorted someplace...

There is also a 2A fuse missing..

Andi

I'd disconnect the secondaries (maybe just pull the fuses?), and power it via a lamp limiter and/or Variac.

Courtney Louise · 24th Mar 2006, 7:17 pm

I get a resistance of 5.5R on the primary winding

Its not showing any continuity to any of the secondaries

Nickthedentist · 24th Mar 2006, 7:23 pm

Quote:

Originally Posted by Jarl Ayari

I get a resistance of 5.5R on the primary winding

Its not showing any continuity to any of the secondaries

I would expect a few tens of ohms on the primary

Time to track down the service data, and then a replacement transformer, I fear

Nick.

Courtney Louise · 24th Mar 2006, 7:32 pm

Something tells me one may be easier than the other.. and that this may not be a viable restoration...

Andi

Duke_Nukem · 24th Mar 2006, 8:17 pm

Is it a model TPGII ? Four chassis with following valves :-

Lock chassis : ECC34 + 6D2
RF Unit : 6L18 + 6F33
Power Unit : GZ32
Modulator chassis : 12(!)*ECC34, 6 * 6F13, 4 * 6D2 ?

In which case I have both the service manual and the user manual. Also with that many heaters it is going to be quite some transformer and a primary measuring quite low ohms wouldn't suprise me. And the secondary winding that powers all them ECC34's must be pretty thick, I can't believe it'd go o/c.

I wouldn't write off the transformer just yet, I had a fergy radio which must have emptied it's entire wax content all over the bottom of the cabinet yet that part of the radio worked fine. Pull out the valves and connect to the mains via a lamp limiter before condemning it.

TTFN,
Jon

Courtney Louise · 24th Mar 2006, 9:07 pm

I think Mine is a TPGII

The exact item code on the front reads

Murphy Radio Ltd
TELEVISION
PATTERN GENERATOR
TYPE II NO 4238/1041

And the PSU is seperate.

MURPHY RADIO LTD
POWER SUPPLY TYPE A
SERIAL NO. 4229/1041

I think maybe its similar to what you have the manuals for. I think I counted 13 ECC34's in there, thats a lot of valves...

Andi

Courtney Louise · 24th Mar 2006, 9:09 pm

Jon,

Mine is 2 seperate units but the valve lineup sounds very similar. I cant be far from you is there any chance I could be cheeky and ask to borrow the service/users manuals please?

Andi

Ed_Dinning · 24th Mar 2006, 9:31 pm

Hi Jarl, all may not be lost as the tranny could be replaced with a different type if it is not important to keep chassis originality.
The HT current may be quite low 50/100mA at possibly only 250 V. Heater transformers for 10A at 6.3 V can also be found fairly easily. There is always a re-wind but that could be more expensive.

HTH Ed

Courtney Louise · 24th Mar 2006, 10:00 pm

I have an absolutly monsterous tranny out of a Yaesu FTdx401 Tranciever.. But need to find out what secondaries I need first

I dont think a rewind would be viable... I dont think the kit is worth that much is it?

Andi

jelida · 24th Mar 2006, 10:53 pm

Hi Andi,

I note the vendor listed it as working - perhaps it was, even if overheating. I would remove the surplus wax, replace the power supply capacitors and run it solo, bringing it up slowly on a variac, monitoring HT output (if any) as you go. I have often seen this sort of situation in valve amplifiers, usually due to smoothing cap failure. The trannies are often OK when the fault is sorted.
Good luck!
I was watching this myself, but could not have justified a 300mile round trip to collect it.
Do Pattern Generators often turn up at the NVCF?

regards,
Jerry

Courtney Louise · 24th Mar 2006, 11:00 pm

Hi Jerry

Oh it was certainly a great journey as I ended up with most of the contents of the tv shop...

but it hadnt been tested...

I dont yet have a variac, thats my next purchase...

Andi

24th Mar 2006, 6:04 pm	#1
Courtney Louise Octode Join Date: Sep 2005 Location: Welshpool, Powys, Wales Posts: 1,327	Murphy 405 line generator HELP!!! Hi guys, I just got this off fleabay and its a bit dead... I opened the PSU and found that the Mains transformer over many many hours ofrunning has decided t leak all of its wax and so has the smoothing choke. Is there any way of fixing this. I have no clue to the voltages its supposed to give nor the currents. Pics of the affected transformer enclosed... Andi Attached Thumbnails __________________ *33, 45, 78, around and around they go...* Last edited by Courtney Louise; 24th Mar 2006 at 6:06 pm. Reason: To add pics

24th Mar 2006, 6:46 pm	#2
tvden Retired Dormant Member Join Date: Oct 2003 Location: Halesworth, Suffolk, UK. Posts: 413	Re: Murphy 405 line generator HELP!!! Hi well I would say your transformer looks cooked, have you a model number for this item? as one of us may have a circuit regards Den

24th Mar 2006, 6:50 pm	#3
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,863	Re: Murphy 405 line generator HELP!!! What a mess However, if the transformer is still OK electrically, all might not be lost. "Migration" of wax and pitch from transformers doesn't necessarily mean they won't work, although obviously it's a sign that they've run far too hot. Removal of the excess wax (hairdryer and plenty of old rags), then eliminating the cause of the hot running (e.g. shorted supply line, leaky coupling caps) has worked for me on several occasions (e.g. my Hacker Mayflower I radio). Nick.

24th Mar 2006, 7:04 pm	#4
Courtney Louise Octode Join Date: Sep 2005 Location: Welshpool, Powys, Wales Posts: 1,327	Re: Murphy 405 line generator HELP!!! Hmmm model number ... Well its a Pattern Generator type II by Murphy. and the PSU is Type A Andi __________________ *33, 45, 78, around and around they go...*

24th Mar 2006, 7:06 pm	#5
Courtney Louise Octode Join Date: Sep 2005 Location: Welshpool, Powys, Wales Posts: 1,327	Re: Murphy 405 line generator HELP!!! I must admit to having not tried powering it up as I know some of the caps need changing and if its gotten that hot (looks like its been a long tim in happening tho) then I am guessing its shorted someplace... There is also a 2A fuse missing.. Andi __________________ *33, 45, 78, around and around they go...*

24th Mar 2006, 7:17 pm	#7
Courtney Louise Octode Join Date: Sep 2005 Location: Welshpool, Powys, Wales Posts: 1,327	Re: Murphy 405 line generator HELP!!! I get a resistance of 5.5R on the primary winding Its not showing any continuity to any of the secondaries __________________ *33, 45, 78, around and around they go...*

24th Mar 2006, 7:32 pm	#9
Courtney Louise Octode Join Date: Sep 2005 Location: Welshpool, Powys, Wales Posts: 1,327	Re: Murphy 405 line generator HELP!!! Something tells me one may be easier than the other.. and that this may not be a viable restoration... Andi __________________ *33, 45, 78, around and around they go...*

24th Mar 2006, 8:17 pm	#10
Duke_Nukem Octode Join Date: Jan 2003 Location: Birmingham, West Midlands, UK. Posts: 1,268	Re: Murphy 405 line generator HELP!!! Is it a model TPGII ? Four chassis with following valves :- Lock chassis : ECC34 + 6D2 RF Unit : 6L18 + 6F33 Power Unit : GZ32 Modulator chassis : 12(!)ECC34, 6 6F13, 4 * 6D2 ? In which case I have both the service manual and the user manual. Also with that many heaters it is going to be quite some transformer and a primary measuring quite low ohms wouldn't suprise me. And the secondary winding that powers all them ECC34's must be pretty thick, I can't believe it'd go o/c. I wouldn't write off the transformer just yet, I had a fergy radio which must have emptied it's entire wax content all over the bottom of the cabinet yet that part of the radio worked fine. Pull out the valves and connect to the mains via a lamp limiter before condemning it. TTFN, Jon

24th Mar 2006, 9:07 pm	#11
Courtney Louise Octode Join Date: Sep 2005 Location: Welshpool, Powys, Wales Posts: 1,327	Re: Murphy 405 line generator HELP!!! I think Mine is a TPGII The exact item code on the front reads Murphy Radio Ltd TELEVISION PATTERN GENERATOR TYPE II NO 4238/1041 And the PSU is seperate. MURPHY RADIO LTD POWER SUPPLY TYPE A SERIAL NO. 4229/1041 I think maybe its similar to what you have the manuals for. I think I counted 13 ECC34's in there, thats a lot of valves... Andi __________________ *33, 45, 78, around and around they go...*

24th Mar 2006, 9:09 pm	#12
Courtney Louise Octode Join Date: Sep 2005 Location: Welshpool, Powys, Wales Posts: 1,327	Re: Murphy 405 line generator HELP!!! Jon, Mine is 2 seperate units but the valve lineup sounds very similar. I cant be far from you is there any chance I could be cheeky and ask to borrow the service/users manuals please? Andi __________________ *33, 45, 78, around and around they go...*

24th Mar 2006, 9:31 pm	#13
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,195	Re: Murphy 405 line generator HELP!!! Hi Jarl, all may not be lost as the tranny could be replaced with a different type if it is not important to keep chassis originality. The HT current may be quite low 50/100mA at possibly only 250 V. Heater transformers for 10A at 6.3 V can also be found fairly easily. There is always a re-wind but that could be more expensive. HTH Ed

24th Mar 2006, 10:00 pm	#14
Courtney Louise Octode Join Date: Sep 2005 Location: Welshpool, Powys, Wales Posts: 1,327	Re: Murphy 405 line generator HELP!!! I have an absolutly monsterous tranny out of a Yaesu FTdx401 Tranciever.. But need to find out what secondaries I need first I dont think a rewind would be viable... I dont think the kit is worth that much is it? Andi __________________ *33, 45, 78, around and around they go...*

24th Mar 2006, 10:53 pm	#15
jelida Pentode Join Date: Mar 2006 Location: Pontypool, South Wales, UK. Posts: 140	Re: Murphy 405 line generator HELP!!! Hi Andi, I note the vendor listed it as working - perhaps it was, even if overheating. I would remove the surplus wax, replace the power supply capacitors and run it solo, bringing it up slowly on a variac, monitoring HT output (if any) as you go. I have often seen this sort of situation in valve amplifiers, usually due to smoothing cap failure. The trannies are often OK when the fault is sorted. Good luck! I was watching this myself, but could not have justified a 300mile round trip to collect it. Do Pattern Generators often turn up at the NVCF? regards, Jerry

24th Mar 2006, 11:00 pm	#16
Courtney Louise Octode Join Date: Sep 2005 Location: Welshpool, Powys, Wales Posts: 1,327	Re: Murphy 405 line generator HELP!!! Hi Jerry Oh it was certainly a great journey as I ended up with most of the contents of the tv shop... but it hadnt been tested... I dont yet have a variac, thats my next purchase... Andi __________________ *33, 45, 78, around and around they go...*