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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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22nd Jun 2009, 4:52 pm | #1 |
Retired Dormant Member
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Location: leeds
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hacker mayflower 2
I am trying to restore a mayflower, The output stage has been over running, I have changed the coupling caps. and the anode and cathode resistors along with assosiated decoupling caps. But I have the problem of R34 cooking it's self to death even though I have replaced C27. Anybody point me in the right direction please?
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22nd Jun 2009, 5:00 pm | #2 |
Dekatron
Join Date: Sep 2003
Location: Bolton, Greater Manchester, UK.
Posts: 6,644
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Re: hacker mayflower 2
Using the manufacturer's sheet, try C38, Pull V1 and see if it still overheats.
Cheers, Steve P.
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22nd Jun 2009, 6:01 pm | #3 |
Nonode
Join Date: Dec 2002
Location: Coulsdon, Surrey, UK.
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Re: hacker mayflower 2
I agree with Steve, almost certainly C38
Also possible is a short within the tuner assembly ( ie metal cover touching, if there is one ?? ) Forget that - I've just noticed that the HT supply resistors appear to be outside of the tuner head. What does the C28 end of R34 to ground measure (ohms ) Also, what is the voltage across R34 ? Andy |
22nd Jun 2009, 7:09 pm | #4 |
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Re: hacker mayflower 2
Iv'e changed C38
Volts across R34 = 77v it reaches a temp of 50 degrees C after about 5 mins. Ohms to chasis junction C28/R34 rises in M ohms until my digital meter reads overload. |
22nd Jun 2009, 7:23 pm | #5 |
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Join Date: Sep 2003
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Re: hacker mayflower 2
Pull out V1 and see if it overheats then.
Change R34. Cheers, Steve P,
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If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...? |
22nd Jun 2009, 7:25 pm | #6 |
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Re: hacker mayflower 2
Scrub the bit about meter showing overload iv'e done it again and the resistance started at 112K but is very slowly going down the longer i have the meter conected
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22nd Jun 2009, 11:02 pm | #7 |
Nonode
Join Date: Dec 2002
Location: Coulsdon, Surrey, UK.
Posts: 2,109
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Re: hacker mayflower 2
From your measurements the current through R34 is only c. 11ma which seems reasonable for the tuner head.
Also, the power being dissipated, assuming R34 actually measures 6k8 is only just under 0.9 watts, so this doesn't look like a fault, as such. If double checking the measurements gives the same readings, you need a higher wattage resistor perhaps ?? Andy |
23rd Jun 2009, 5:40 pm | #8 |
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Join Date: Mar 2008
Location: leeds
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Re: hacker mayflower 2
I removed V1 and R34 was cool, Being a beginer what should removing V1 tell me?
I have a 2W resistor to replace R34, I will change it and see what happens |
23rd Jun 2009, 5:43 pm | #9 |
Dekatron
Join Date: Sep 2003
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Re: hacker mayflower 2
Fit a 2W resistor like you said and you should be OK. Good sounding sets.
Cheers, Steve P.
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If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...? |
1st Aug 2009, 5:02 pm | #10 |
Retired Dormant Member
Join Date: Mar 2008
Location: leeds
Posts: 14
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Re: hacker mayflower 2
Sorry it's taken so long to say thankyou to all that helped but I have been in France getting even more sets !!!
Dave |