Marconiphone T69 Da - no reception - UK Vintage Radio Repair and Restoration Discussion Forum

bosscock · 25th Apr 2009, 9:18 am

Hi everyone,

i have a T69 which has had the waxies replaced. there is audio from the speakers, but no reception on any of the bands.

upto now i have checked the following:

1.switch cleaned the waveband switch.
2. checked voltage at valve bases, there is HT although I'm unsure at to what they should read as I can't find details on the trader sheet.
3. Have just bought a signal probe (see attached 99p ebay,1960's looking) when i input a signal at the valve bases I can hear the tone through the speaker. when I inject the signal at the ferrite coils i can also hear a tone. No tone at the aerial input.

any suggestions as to where to check now, would be greatly appreciated

Steve_P · 25th Apr 2009, 9:58 am

Put the probe down and do the following checks:

Put an aerial in. Silly I know, but you would be amazed!
Get the circuit from up top there and check that all the waxies are in the right places.
And the valves for that matter.
Do you get any noise (crackles) when you operate the Wavechange switch?

We'll take it from there.

Cheers,

Steve P.

kestrelmusic · 25th Apr 2009, 10:06 am

If you get the RTVS service sheet is shows the correct valve voltages. It can be obtained from www.service-data.com .

Personally, I would distrust the wavechange switch. Is there anything getting through on FM?

bosscock · 25th Apr 2009, 10:41 am

Thanks for the quick reply,
have put the probe down...
put the aerial in makes no differnece not even a crackle.
I've already got the trader sheet, are the voltages the numbers in boxes ie. am 97 fm 42. (near valve 2)

bosscock · 25th Apr 2009, 10:50 am

nothing on FM Kestrel

bosscock · 25th Apr 2009, 10:52 am

wavechange switch= crackle MW to FM but doesn't crackle changing from LW to MW

Station X · 25th Apr 2009, 12:25 pm

Quote:

Originally Posted by bosscock

I've already got the trader sheet, are the voltages the numbers in boxes ie. am 97 fm 42. (near valve 2)

That's correct. The readings will differ depending on whether the set is switched to AM or FM. Voltages should be measured with respect to the chassis. If you're using a digital multimeter (DMM) expect the voltages to measure slightly higher.

bosscock · 25th Apr 2009, 12:53 pm

just check v1 and v2 on fm

v1=
pin 1 should be 125 measured at 132
pin 6 should be 115 measure at 142

v2=
pin 1 should be 75 measured at 74
pin8 should be 42 measured at 81

Steve_P · 25th Apr 2009, 5:50 pm

Home from the radio station and just had a look at the circuit.

If the Audio gets out from the Anode of V4 (Pin 9) and Grid (Pin 8) then check with your voltmeter around V3. Should be 183v on AM, 173v on FM on the Anode (Pin 7). If not, check for volts on R21.

Should have volts on Pin 8 too, if not check volts on R20 and change C44.

On V2, Should be 97v on AM and 42v on FM.

If you haven't done so already, check the wavechange switch. Also check R14 and the volts on Pin 6 of V2.

Check and post results.

Cheers,

Steve P.

bosscock · 25th Apr 2009, 6:32 pm

THanks for the reply Steve, off for a Ruby tonight will check in the morning and feed back.

bosscock · 27th Apr 2009, 3:31 pm

right....

V4 :
pin 9 audio present and changes with volume
pin 8 audio present no change with voulume

V3:
pin 7 FM=212v LW=219v
pin 8 = 1v

v2
pin8 FM=30v Lw=35v
pin6 193

r20 = 181 volts one side 0 volts no other (possible open?) unable to get ohmns reading

will check r14 and r21 when i can trace them on the circuit board..( first pcb and its a bit on a maze)

and have a look at hte waveband switch
thanks again

Neill

Steve_P · 27th Apr 2009, 5:53 pm

Check R20 and C44.

Cheers,

Steve P

bosscock · 27th Apr 2009, 7:49 pm

replaced r20 and c44

FM coming through loud and clear

so happy

one or two channels on mw around 200
LW silent..
... thankyou very very much Steve... for the help and the patience.

Steve_P · 27th Apr 2009, 8:15 pm

Right. Now for MW and LW. Examine and thoroughly clean the Wavechange switch.

Cheers,

Steve P.

bosscock · 28th Apr 2009, 1:50 pm

I managed to get a cotton bud with switch cleaner onto the contacts (both sides, very gently) i was surprised at the change from black to copper. Still no change.

I can pick up a few faint stations on mw.
thanks in advance
Neill

Steve_P · 29th Apr 2009, 7:27 pm

Have you got a signal generator?

Cheers,

Steve P.

bosscock · 30th Apr 2009, 1:17 pm

No, sorry, only been on the scene for a month or two. multimeter and signal injector.
Neill

Steve_P · 30th Apr 2009, 2:35 pm

OK, well we'll hope the IF's are OK.

Check C34, C12, C30.

Put an aerial directly on Pin 2 of the UCH81.

Cheers,

Steve P.

julie_m · 30th Apr 2009, 4:39 pm

Check whether the local oscillator is running (a dirty wavechange switch can easily stop it). You can do this using any MW battery portable set -- if you don't know how, I can post a write-up.

benjamin77 · 30th May 2009, 4:12 pm

Ok a few questions on this one as I have the same set...!

Mine is working only on MW...silent on VHF and LW! I have tried the same things (external Arial and cleaning the wave change switch) but still no luck....

Having worked out what the capacitor colour code would be,Yellow,Violet,Orange,Silver I think I have located the correct one on the PCB and it gives a reading of 53.1 not 47. As this is out of the 10% tollerance range if by only a small amount does it need changing?

Secondly and this will probably make me sound like a complete fool I get confused and dont really understand how to take readings fom valve pins as I am unsure of how they are numberd......
Cheers

25th Apr 2009, 9:18 am	#1
bosscock Retired Dormant Member Join Date: Mar 2009 Location: southport UK Posts: 49	Marconiphone T69 Da - no reception Hi everyone, i have a T69 which has had the waxies replaced. there is audio from the speakers, but no reception on any of the bands. upto now i have checked the following: 1.switch cleaned the waveband switch. 2. checked voltage at valve bases, there is HT although I'm unsure at to what they should read as I can't find details on the trader sheet. 3. Have just bought a signal probe (see attached 99p ebay,1960's looking) when i input a signal at the valve bases I can hear the tone through the speaker. when I inject the signal at the ferrite coils i can also hear a tone. No tone at the aerial input. any suggestions as to where to check now, would be greatly appreciated Attached Thumbnails

25th Apr 2009, 9:58 am	#2
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Marconiphone T69 Da - no reception Put the probe down and do the following checks: Put an aerial in. Silly I know, but you would be amazed! Get the circuit from up top there and check that all the waxies are in the right places. And the valves for that matter. Do you get any noise (crackles) when you operate the Wavechange switch? We'll take it from there. 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...?

25th Apr 2009, 10:06 am	#3
kestrelmusic Hexode Join Date: Feb 2008 Location: Wrexham, North Wales, UK. Posts: 466	Re: Marconiphone T69 Da - no reception If you get the RTVS service sheet is shows the correct valve voltages. It can be obtained from www.service-data.com . Personally, I would distrust the wavechange switch. Is there anything getting through on FM?

25th Apr 2009, 10:41 am	#4
bosscock Retired Dormant Member Join Date: Mar 2009 Location: southport UK Posts: 49	Re: Marconiphone T69 Da - no reception Thanks for the quick reply, have put the probe down... put the aerial in makes no differnece not even a crackle. I've already got the trader sheet, are the voltages the numbers in boxes ie. am 97 fm 42. (near valve 2)

25th Apr 2009, 10:50 am	#5
bosscock Retired Dormant Member Join Date: Mar 2009 Location: southport UK Posts: 49	Re: Marconiphone T69 Da - no reception nothing on FM Kestrel

25th Apr 2009, 10:52 am	#6
bosscock Retired Dormant Member Join Date: Mar 2009 Location: southport UK Posts: 49	Re: Marconiphone T69 Da - no reception wavechange switch= crackle MW to FM but doesn't crackle changing from LW to MW

25th Apr 2009, 12:53 pm	#8
bosscock Retired Dormant Member Join Date: Mar 2009 Location: southport UK Posts: 49	Re: Marconiphone T69 Da - no reception just check v1 and v2 on fm v1= pin 1 should be 125 measured at 132 pin 6 should be 115 measure at 142 v2= pin 1 should be 75 measured at 74 pin8 should be 42 measured at 81

25th Apr 2009, 5:50 pm	#9
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Marconiphone T69 Da - no reception Home from the radio station and just had a look at the circuit. If the Audio gets out from the Anode of V4 (Pin 9) and Grid (Pin 8) then check with your voltmeter around V3. Should be 183v on AM, 173v on FM on the Anode (Pin 7). If not, check for volts on R21. Should have volts on Pin 8 too, if not check volts on R20 and change C44. On V2, Should be 97v on AM and 42v on FM. If you haven't done so already, check the wavechange switch. Also check R14 and the volts on Pin 6 of V2. Check and post results. 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...?

25th Apr 2009, 6:32 pm	#10
bosscock Retired Dormant Member Join Date: Mar 2009 Location: southport UK Posts: 49	Re: Marconiphone T69 Da - no reception THanks for the reply Steve, off for a Ruby tonight will check in the morning and feed back.

27th Apr 2009, 3:31 pm	#11
bosscock Retired Dormant Member Join Date: Mar 2009 Location: southport UK Posts: 49	Re: Marconiphone T69 Da - no reception right.... V4 : pin 9 audio present and changes with volume pin 8 audio present no change with voulume V3: pin 7 FM=212v LW=219v pin 8 = 1v v2 pin8 FM=30v Lw=35v pin6 193 r20 = 181 volts one side 0 volts no other (possible open?) unable to get ohmns reading will check r14 and r21 when i can trace them on the circuit board..( first pcb and its a bit on a maze) and have a look at hte waveband switch thanks again Neill

27th Apr 2009, 5:53 pm	#12
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Marconiphone T69 Da - no reception Check R20 and C44. 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...?

27th Apr 2009, 7:49 pm	#13
bosscock Retired Dormant Member Join Date: Mar 2009 Location: southport UK Posts: 49	Re: Marconiphone T69 Da - no reception replaced r20 and c44 FM coming through loud and clear so happy one or two channels on mw around 200 LW silent.. ... thankyou very very much Steve... for the help and the patience.

27th Apr 2009, 8:15 pm	#14
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Marconiphone T69 Da - no reception Right. Now for MW and LW. Examine and thoroughly clean the Wavechange switch. 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...?

28th Apr 2009, 1:50 pm	#15
bosscock Retired Dormant Member Join Date: Mar 2009 Location: southport UK Posts: 49	Re: Marconiphone T69 Da - no reception I managed to get a cotton bud with switch cleaner onto the contacts (both sides, very gently) i was surprised at the change from black to copper. Still no change. I can pick up a few faint stations on mw. thanks in advance Neill

29th Apr 2009, 7:27 pm	#16
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Marconiphone T69 Da - no reception Have you got a signal generator? 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...?

30th Apr 2009, 1:17 pm	#17
bosscock Retired Dormant Member Join Date: Mar 2009 Location: southport UK Posts: 49	Re: Marconiphone T69 Da - no reception No, sorry, only been on the scene for a month or two. multimeter and signal injector. Neill

30th Apr 2009, 2:35 pm	#18
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Marconiphone T69 Da - no reception OK, well we'll hope the IF's are OK. Check C34, C12, C30. Put an aerial directly on Pin 2 of the UCH81. 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...?

30th Apr 2009, 4:39 pm	#19
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Marconiphone T69 Da - no reception Check whether the local oscillator is running (a dirty wavechange switch can easily stop it). You can do this using any MW battery portable set -- if you don't know how, I can post a write-up. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

30th May 2009, 4:12 pm	#20
benjamin77 Retired Dormant Member Join Date: May 2009 Location: High Wycombe, Buckinghamshire, UK. Posts: 326	Re: Marconiphone T69 Da - no reception Ok a few questions on this one as I have the same set...! Mine is working only on MW...silent on VHF and LW! I have tried the same things (external Arial and cleaning the wave change switch) but still no luck.... Having worked out what the capacitor colour code would be,Yellow,Violet,Orange,Silver I think I have located the correct one on the PCB and it gives a reading of 53.1 not 47. As this is out of the 10% tollerance range if by only a small amount does it need changing? Secondly and this will probably make me sound like a complete fool I get confused and dont really understand how to take readings fom valve pins as I am unsure of how they are numberd...... Cheers