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Old 15th Jan 2019, 11:32 am   #41
Humptydumpty
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Default Re: Trio 9R-59D receiver problems.

Graham just one thing .Do i check these readings from under the chassis with the valve in situ . Or do i pull the valve out of its holder and put the test probe of the meter in the holes showing. I removed the valve to test the pin outputs going anti clockwise . .No one said , or told me to do it i just thought it was from above
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Old 15th Jan 2019, 11:36 am   #42
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Default Re: Trio 9R-59D receiver problems.

If you're measuring voltages you need to have the set switched on and the valve in its socket.

If you're measuring resistances you need to have the set switched off. In this case it won't matter whether the valve is in its socket or not. It's obviously easier to check the cathode resistor by removing the valve and connecting your meter between chassis and pin 2. As you say when looking form above the pins number anti-clockwise.
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Old 15th Jan 2019, 11:44 am   #43
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Default Re: TRIO 9R- 59D Question

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Originally Posted by Humptydumpty View Post
I was told by a good forum member to reposition the small transformer and fit it under the chassis .This was done .This move made no change and i still have this hum. I know very little in repair of such items .But i am going to stop this hum if i can before it and the FROG7 both go away for service .
It was the output transformer i moved to another location under the chassis .The mains transformer is too big a job for me .
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Old 15th Jan 2019, 11:50 am   #44
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Default Re: Trio 9R-59D receiver problems.

So i did that right .From above with valve out anticlockwise . Pin 5 = 210 volts this is ok ? and pin 1= 2 volts . . Talk later on about next step.
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Old 15th Jan 2019, 11:55 am   #45
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Default Re: Trio 9R-59D receiver problems.

2 Volts on pin 1 is bad. It'll be caused by C34 being electrically leaky. Disconnect one end of C34 and check pin 1 again. If the reading has dropped to close to zero C34 is the problem and needs replacing.

The is the same problem I had with my set.

https://www.vintage-radio.net/forum/...d.php?t=127728
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Old 15th Jan 2019, 3:25 pm   #46
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Default Re: Trio 9R-59D receiver problems.

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Quote:
Originally Posted by Phil G4SPZ View Post
So far, he has successfully replaced the volume control and the receiver is working, but with constant hum. He has established that the HT at the anode of the output valve (pin 5) is only about 40 volts instead of the normal 200 volts. I have now asked Trevor to measure the valve’s cathode voltage to see whether the low HT is being caused by excessive current draw through the output valve or simply by a faulty reservoir capacitor.
Remove the output valve, measure the anode volts, if then ok try another valve, lots of these available.
On the subject of hum (unrelated to low HT) please check for dc volts on the input grid of the valve, if any found replace the capacitor on the grid, does not need to be exact value, it allows the AF to get to the valve and isolates the grid from DC.
you will fix this radio as very simple circuit and also these preform very good

MM0HDW
YES relocate the output Xmer, had to do that on three of these sets, this removed the hum but still check all other sources of hum, smoothing, leaky grid cap, bad valve.
The mods of 1971 radio mags greatly improved these sets. Fit the voltage stabilizer, improve the vfo stability. control of Rf stage etc.
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Old 15th Jan 2019, 5:29 pm   #47
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Default Re: Trio 9R-59D receiver problems.

Graham just returned from the weekly shoping trip .And i have a cold but i had to go out . And my friend next door has his wife bed ridden and not well enough himself so i do his shoping as well. Therfore i had no option but to go .
I see the C34 on the map lol [ schematic diagram ] so i will remove the bottom cover and then disconnect one side of it . Then come back with the news Wednesday.Your a star Graham ...
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Old 16th Jan 2019, 10:39 am   #48
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Default Re: Trio 9R-59D receiver problems.

Thank you James for that information . And all the valves have been replaced the last 2 yesterday . No change .Even changed ext speaker in case it was faulty.
Going back to Graham . Last night i removed the bottom of the receiver but looking in at the base of v8 i can see no C34 i took pictures to post up but i am not able to do that on the forum .Are these C34 about the size of a 1p and coated ? The schematic shows 4 C3-s i can see none of them at all on the base of v8 .
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Old 16th Jan 2019, 10:47 am   #49
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Default Re: Trio 9R-59D receiver problems.

I think you'll find that as this set uses a Printed Circuit Board (PCB), C34 is mounted on the same upper side of the PCB as the valve. However it will have to be unsoldered by melting the solder on the lower side of the PCB.

Give me a bit of time and I'll take a picture of the repair I made to my own set.

EDIT. Would you believe I still have the faulty capacitor C34? It is grey 16mm long, 8mm diameter and has .01 uF written on it.

FURTHER EDIT. If you look in the service manual you'll find a drawing showing the layout of the components on the PCB. C34 is clearly shown.
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Old 16th Jan 2019, 11:23 am   #50
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Default Re: Trio 9R-59D receiver problems.

Top marks Graham . Yes i was looking in the wrong place ,as you say its sited on the top side next to the valve V8 reads 0.01 uf [M] 600 wv is this the one ? looks like there are 4 of them the one you talk about and thee smaller ones .
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Old 16th Jan 2019, 11:26 am   #51
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Default Re: Trio 9R-59D receiver problems.

That's the one! Made by RightCon Japan.
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Old 16th Jan 2019, 11:56 am   #52
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Default Re: Trio 9R-59D receiver problems.

Graham looking in the schematic the values they are 25 wv a 150wv and 400wv and last one is 600 wv . Then looking at the schematic the C34 is 0.01uf 20 % + or - the one i am looking at is 25 wv .
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Old 16th Jan 2019, 12:00 pm   #53
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Default Re: Trio 9R-59D receiver problems.

The capacitor you have to disconnect is C34. Its capacitance is .01uF and its working voltage (WV) is 600V. Mine is actually 630 WV, but it doesn't matter.

You clearly identified it in post #50.
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Old 16th Jan 2019, 12:13 pm   #54
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Default Re: Trio 9R-59D receiver problems.

Graham not questioning your knowledge but if you have your schematic .Could you just check .Mine reads in the service manual that C34 is 25 WV why is there no value only 25 % + or WV - ? Trev
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Old 16th Jan 2019, 12:48 pm   #55
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Default Re: Trio 9R-59D receiver problems.

I've looked at the service manual.

In the parts list is doesn't actually give a working voltage for C34. It says it's a 0.01uF with a tolerance of plus or minus 20%.

The circuit diagram simply says C34 0.01.

The PCB layout says C34 .01.

The component itself is labelled

CP-C
.01uF (M)
630WV
RightCon
Japan

There is no conflict between any of the above values.
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Old 16th Jan 2019, 12:50 pm   #56
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Default Re: Trio 9R-59D receiver problems.

So next step Graham is to temove that 600wv capacitor . Jusr doublechecked and it is showing 2 volt steady fron pin one ant /c . Come back later after i remove this capacitor from one side .
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Old 16th Jan 2019, 12:52 pm   #57
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Default Re: Trio 9R-59D receiver problems.

So another way to identifie this is its the highest value being 600wv .Thank you back later on after its removed on one side .
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Old 16th Jan 2019, 1:01 pm   #58
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Default Re: Trio 9R-59D receiver problems.

I've emailed you a copy of the service manual so that we can be certain that we're both singing from the same hymn sheet.

The capacitor to disconnect is that which I described in some detail in post #55.
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Old 16th Jan 2019, 1:31 pm   #59
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Default Re: Trio 9R-59D receiver problems.

Graham succsess , it now shows zero voltage at pin one ,I will remove the capacitor eventual,ly and replace it with another one .Looking on ebay i see nothing with the same value, would you have info on the location of one of these capacitor. I looked on cpc only to find hundreds and its confusing and not easy to choose the right part .Thank you for the step by step tuition .I might just get this sorted with your help.
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Old 16th Jan 2019, 1:36 pm   #60
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Default Re: Trio 9R-59D receiver problems.

PM me your address and I'll send you a replacement cap FOC. It's the easiest way to go.
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