PYE 15A volume

[Ronners]

No sound at all Alan V3 pin 8 now reads 235. Have done the pic of the Daly cap can you please tell me how to post it tried drag and drop but no joy.

[snowman_al]

Post pictures:
Scroll down from the message pane,
look for 'Manage Attachments'. Click on it and another window opens.
Click on the top 'Choose File'. Select the picture you want and click open. Once the image number is next to the Choose File box, click Upload. The picture will appear in the 'attachments'.

235 volts on pin 8 suggests either the EBL31 is short, or there is a problem with R11 and or R12. (235 volts on the 22uF 100v cap would explain the pop! I expect the old Daly is open circuit so not effected...)
What value resistor did you put in the R12 position?
Next remove V3 and measure the resistance from pin 8 to the chassis.

Alan

[Sideband]

Originally Posted by snowman_al

What value resistor did you put in the R12 position?
Next remove V3 and measure the resistance from pin 8 to the chassis.

Alan

Is R12 the cathode resistor? If this is the wrong value or open circuit that might explain why the voltage is now so high. If the cathode resistor is open circuit, the cathode of the valve will tend to rise towards HT level....hence the 235V reading and why your 100V cap went pop! I think R12 should be 330 ohms. If you have put in a 33k or worse a 330K then that would explain the high voltage. Make sure you have the correct value for R12. If in doubt, measure it.

[snowman_al]

Yes R11 (150R) and R12 (470R) are the cathode resistors.

If Ron measures from the cathode (pin 8) to chassis we will know soon enough if there is a dis-connection or maybe wrong value...

[Ronners]

Hi Allan just been down and done a quick reading on R12 nothing at all till I switched the meter to 200K setting then I got 460 looks like I made a boob with the resistor order is all lost?

[Silicon]

The reading on the display of the multimeter is a bit confusing.

Do you have a moving coil or a modern digital multimeter?
When you saw 460 on the multimeter, was there a dot between the 6 and the 0?

What are the colours of the bands on the resistor R12?

Please also measure the resistance between chassis and the cathode of V3 (when the set is not powered).

[snowman_al]

Originally Posted by Ronners

Hi Allan just been down and done a quick reading on R12 nothing at all till I switched the meter to 200K setting then I got 460 looks like I made a boob with the resistor order is all lost?

No it will be fine.
Slowly now, one thing at a time.

First, make sure the resistor you have for R12 is 470 ohms. What value did you order?

Did you mix the resistors up when you replaced R3 and R4 at the same time? R3 should be 47K ohms (47,000 ohms). Look back and make sure that is what you fitted there. Confusing ehy?

It would be much easier to help if you could post some good pictures of the chassis now, before you 'mend' anything else. We can see the resistors and check the values for you.

Now you need to order a replacement 22uF cap to replace C19 (the Daly is dead...) and a 470 ohm 1 or 2 watt resistor for R12 if you did not get the correct value before.

When you have replaced them, before you plug it in, please measure the resistance from V3 pin 8 to the chassis. It should be 600 - 620 ohms. (R11 + R12 = 620 ohms.)
If it is, then plug it in and all being well you should measure a voltage on that pin 8 of around 20 volts. If not switch off quickly.

Enough for now, and pictures please if you can, Alan

[Silicon]

The radio will work without C19.

Once the voltage at pin 8 of V3 is correct, you can then add C19.

[Ronners]

HI Alan hope you have received the pics ok the resistors I bought are 0.25w 150 ohm,0.25w 470 ohm & 2w 47K ohm. Best regards Ron H.

[Silicon]

The 150 Ohm 0.25W resistor should be OK but the 470 Ohm resistor should be rated at 1Watt or more.

R12 will be dissipating 0.54 Watt approximately when the radio is on.
It could start smouldering after 30 seconds!

[snowman_al]

Ron hi,
The 1/4 watt resistors are t o o small for the output valve cathode location, R11 and R12. Do not even try the set again until you replace them with higher wattage types.
They have to be at least 1 watt, better that they are 2 watt types, as advised. In normal operation they will be dissipating 0.5 to 0.6 watts and could be more depending on the condition of the EBL31. The 0.25 watters will be under considerable stress and perhaps are the fault?

Replace them then please carry out the test in post no. 47

Looking at the picture, thanks, what voltage rating are the red and green capacitors you have used as replacements?

Alan

As silicon says... slow typing here tonight

[Ronners]

Ordered new capacitor and resistor. Will have to look at my orders to try and find out what voltage the red and green caps are. Thank you Alan. Best regards Ron H.

[Sideband]

I can't see the colour code on that resistor too well. It doesn't look like a 150 ohm, a 470 ohm or a 47K....unless it's one of those new-fangled four or five colour band types. What resistor is it, what are the colour codes of the resistors you have bought?

[Ronners]

Red and green cap voltages 0.1uf 630v,0.022uf 250v,0.047uf 250v & 4.7nf 100v. Sorry you cant see the colour code on R 12 I took several pics but none showed up colour code yellow, blue,orange,gold, I put the meter on and it reads 45k ohms as I said earlier I made a boob with my order I have now ordered a 470 ohm 2w replacement. Thanks for all your help. Best regards Ron H.

[Sideband]

46K 5%....odd value....not one of the 'standard' values. 470 ohm is yellow violet brown with either a silver (10%) or gold (5%) tolerance band.

You should aim for 400V or 630V types which will cover most applications in a valve radio. The 250v and 100V types will probably be OK in tone control and AGC circuits but I wouldn't use them anywhere else. If your 250V types are couplers or decouplers, change them for (at least) 400V types. Basically change them for the same voltage or higher than the originals.

[Ronners]

OK folks looks like I need to beef up the caps I fitted I have managed to locate most of them but for the 20nf 750v the nearest I can find are22nf 630v any good ? Best regards Ron H.

[Sideband]

22nF 630V will probably be OK if it's the tone corrector across the output transformer primary since a lot of sets would use a 500V type in this position.

[Ronners]

Ah thanks for that Sideband will order them up. Best regards Ron H.

[Ronners]

OK Chaps now have the correct caps and resistors I have now fitted these and taken a reading as suggested by Alan and indeed the new reading is 614 ohms so I replaced valves and switched on only reception I can get is on long wave and that's just a buzz that increases and decreases as you adjust the tuning. Any ideas ?

[See_Mos]

Take a set of voltage readings around V1,the ECH35
Try another ECH35