Transformer for Kriesler 11-81 Panorama wanted
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Location: Maleny, QLD
Member since 28 February 2018
Member #: 2218
Postcount: 95
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Jonny,
I’ll have a look at this next bit maybe tomorrow night, did you see my little edit to last post? - I found 39k resistor is dead. Not sure if that’s an immediate issue, however I’ll be at jaycar on Saturday. So I’ll take a few days to get back.
Murray
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Location: Hobart, TAS
Member since 31 July 2016
Member #: 1959
Postcount: 574
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The 39k burnt up is another problem, but would also stop it from working but does not explain the very low voltage at the plate of the 6BD7.
The 39k would burn up if for example the bypass cap off it to deck has shorted.
Or the 6AN7 is faulty.
Or the 6N8 is faulty.
Or the valves in this Radio have been plugged into incorrect locations.
It was probably a 10 Minuit fix to start with, now it will take a little longer .
JJ
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Location: Cameron Park, NSW
Member since 5 November 2010
Member #: 770
Postcount: 415
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With the low voltages on the filter caps, I come back to my earlier post re the connections from the transformer to the rectifier plates. Can you confirm that there is about 245V AC at each plate. Your dim bulb should not be in use for these measurements, of course.
If half the secondary winding is open circuit, or the orange wire is wrongly connected, the rectifier is acting as a half wave device resulting in a lower output voltage and also stressing the transformer.
Harold
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Location: Hobart, TAS
Member since 31 July 2016
Member #: 1959
Postcount: 574
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Harold, I think Murray is measuring these voltages with dim bulb in circuit.
But anyway, radio has several other issues to sort out first.
Nothing at this stage appears to be overheating or stressing, and it should be capable of some noises, before we get serious.
I think also he is using an analogue meter with who knows what ohms per volt, or other issues.
Let’s wait till he gets back with the next set of information.
JJ
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Location: Hill Top, NSW
Member since 18 September 2015
Member #: 1801
Postcount: 2120
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Location: Hobart, TAS
Member since 31 July 2016
Member #: 1959
Postcount: 574
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Robbert, He has already done test and has no audio.
He has no audio because the pre amp 6BD7 has virtually no volts on its plate.
Read post 32 re the 39k resistor. (Thats another problem entirely).
And previous posts re 270k feed resistor and coupling cap.
We are waiting for various responses from him before we can proceed.
JJ
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Location: Maleny, QLD
Member since 28 February 2018
Member #: 2218
Postcount: 95
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Johnny,
I have swapped out for another rectifier valve.
Measuring voltages again on that 3.3k resistor, no dim bulb tester( straight 240volts)
Using rapar sk-100 multimeter- 100kohm/v dc, 10k ohm/volt ac, as someone asked.
On the 32mf cap side, (earlier measured 190vdc.) now 235vdc
On the 8 mg cap side , (earlier measured 165vdc) now 165vdc
I have replaced the 39k resistor I mentioned earlier.
All paper and electro caps are new. ( volume pot to pin 2 6bd7)
1 have found that resistor 6 (47k) on the schematic is physically a 270k. It’s newer than all the original resistors, so I’m not sure if I should correct that? It runs from IF transformer to theback of the removable pickup jumper.
I think that’s everything...!
I will keep looking through for errors, that’s a slow process for me as a learner- schematics are a hell of a lot different to house plans.
Murray
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Location: Hobart, TAS
Member since 31 July 2016
Member #: 1959
Postcount: 574
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Well Murray we are still progressing.
From you power supply measurements, and E=IR, then the radio is drawing about 22 milliamperes. Which is good, and nothing is stressing.
What are the voltage measurements now.
Pins 5 and 6 of the 6AQ5
Pin 1 of the 6BD7
Pins 1 and 6 of the 6N8
Pins 1, 7 and 8 of the 6AN7.
JJ
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Location: Maleny, QLD
Member since 28 February 2018
Member #: 2218
Postcount: 95
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Johnny
Straight 240v supply
6aq5 pin 5 480vac. I checked this a few times as it seems high?
Pin 6 345vac
6bd7 pin 1 o volts ac
6n8 pin 1 180vac
pin 6 345vac
6an7 pin 1 17 vac
pin 7 350vac
pin 8 340vac
Murray
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Location: Cameron Park, NSW
Member since 5 November 2010
Member #: 770
Postcount: 415
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Murray
Your meter should be on DC volts setting for these measurements.
Even so, the zero volts on the 6BD7 pin 1 makes R10 or C11 suspect, either open or shorted respectively.
Harold
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Location: Hobart, TAS
Member since 31 July 2016
Member #: 1959
Postcount: 574
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Just a correction to post 38.
Current draw of front end of the radio, 22 milliamperes. Plus whatever the 6AQ5 is drawing.
Yes, Murray we need DC volt measurements.
JJ
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Location: Maleny, QLD
Member since 28 February 2018
Member #: 2218
Postcount: 95
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Johnny
That’s what I said. 🤪
6AQ5 pin 5 212 VDC
Pin 6 160 VDC
6BD7 pin 1 zero VDC
6N8 pin 1 75 VDC
pin 6 160 VDC
6AN7 pin 1 75 VDC
pin 7 160 VDC
pin 8 160 VDC
As far as reading AC or DC, I feel a bit daft there.. I took a punt and lost...
Murray
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Location: Hobart, TAS
Member since 31 July 2016
Member #: 1959
Postcount: 574
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OK, Murray we are getting really close now.
Everything is as I would expect Except for the 6BD7.
There is a wiring error there , Or R10 270K is open circuit, Or C11 150pf short, Or C12 .01 short.
Or 6BD7 faulty.
What voltage do you get on pin 1 with the valve removed?
JJ
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Location: Maleny, QLD
Member since 28 February 2018
Member #: 2218
Postcount: 95
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Johnny
R10 is all good. I lifted that and checked last week.
C11, 150 pf.- I lifted one end, it shows about 500k ohms resistance, so that means not open?
I also note it is from pin 1 to earth in schematic. On the chassis it is on a bus bar, from a wire off pin 1, to another tag, then a red wire leading to centre tag of volume pot.
This might or might not make sense to you.
C12 .01 is new.
I haven’t the ability to test capacitors yet- I have an avometer, but it needs a look over .
I will have to hit jaycar for a replacement possibly.
With valve removed bed still zero vdc on pin 1 6bd7
Murray
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Location: Hobart, TAS
Member since 31 July 2016
Member #: 1959
Postcount: 574
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Definitely a problem, if you have no volts on pin 1 of the 6BD7 with valve removed.
Locate the feed resistor and make sure it goes to pin 1 (270k).
What do you measure either side of this resistor?.(dc voltage).
Lift one end of the 150 pf and leave it off for the moment.
The 150 pf should show infinite resistance, any resistance at all means it’s faulty.
JJ
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