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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc. |
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4th Dec 2016, 1:45 pm | #21 |
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Re: Tandberg 64x after changing capacitors
Before we go any further what meter range did you use when checking those cathodes which should only have 0.5V or 0.8V on them? You need to use a low range for this.
Please confirm that you're using a DC Voltage Range and not AC.
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4th Dec 2016, 1:49 pm | #22 |
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Re: Tandberg 64x after changing capacitors
on the top of the above....
I see there is a 1M resistor connected to that pin 7 where i measured 252V which i think it should not be there....could be that resistor faulty? The other interesting is that I am looking at the prints of the circuit board and noticed that all the pin 4 and 5 are are connected through the tubes...i can go a full circle between them....so all tubes should have 35V on each pins as they should be connected. But out of the 4 tubes, only two has that voltage...so somewhere there must be a broken line or something.... am I seeing this right? |
4th Dec 2016, 1:51 pm | #23 |
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Re: Tandberg 64x after changing capacitors
hmmmm okay...will measure again....i have measured them on 250V setting the lower i can go on my meter is 20V....
which pins I should measure with the lowest voltage? |
4th Dec 2016, 2:02 pm | #24 |
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Re: Tandberg 64x after changing capacitors
20V DC range is better.
Easiest thing to do is start on the highest voltage range and switch down to lower ranges until you get a reading. While you're at it check the HT voltages on the positive sides of C109, C110, C127, C128, C213, C214, C223 and C224.
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4th Dec 2016, 2:24 pm | #25 |
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Re: Tandberg 64x after changing capacitors
One other thought. Do you have the mains voltage selector set to match your mains voltage?
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4th Dec 2016, 2:29 pm | #26 |
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Re: Tandberg 64x after changing capacitors
Thanks Graham.
Did a new readings additional to my previous ones... Some of the pins are still reads 0V ECC83's #1 pin2= 0 pin3= 0,8 pin4+5= 0 pin7=0,8 pin8= 0,8~1.1V pin9= 1,5 V ECC83 #2 pin 2 3 4 5 =0V pin7+8= 0,8 pin 9= 0V ECC83 #3 pin 2,3,4,5= 0 pin 7= 2,2V pin 8= 1,5V pin 9= 1,5~2V ECC83 #4 pin2+3= 0V pin 4+5= 3V pin8=0 pin9= 2,2 V ---------------------------------------- ECC81 #1 pin2= 0,9 pin3= 0,8 pin7= 0,8~5,1 V pin8= 0,8 pin9= 1,1 ECC81 #2 pin2=0,9 pin3=0,6 pin7= 1,7V~7V pin8=0,8 pin9=1,2V ECC82 #1 pin2= 15V pin7= 0,8 pin9=1,2 ECC82 #2 pin2=1,3V pin4=3V pin7=1,5V~20V pin9=1,3V i am getting a bit confused... |
4th Dec 2016, 2:31 pm | #27 |
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Re: Tandberg 64x after changing capacitors
yes...mains set to 250V
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4th Dec 2016, 2:43 pm | #28 |
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Re: Tandberg 64x after changing capacitors
Pins 4, 5 and 9 are all heater pins. If all the valves light up, there should be no need to check these.
However your readings on these pins do not look right. Put you meter on the 20V DC range across pins 4 and 5 of each valve and check that you have 12.6V. That's between pins 4 and 5, not chassis to pins 4 and 5. Your anode readings seem way too high. Did you check the HT voltage on the capacitors?
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4th Dec 2016, 2:56 pm | #29 |
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Re: Tandberg 64x after changing capacitors
all tubes pins 4 and 5 measures 0 Voltage. I didn't check the caps yest, but I have changed the caps you mentioned last week with factory brand new ones...
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4th Dec 2016, 3:01 pm | #30 |
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Re: Tandberg 64x after changing capacitors
Sorry, but if a valve has 0V on its heaters it cannot possibly light up.
Please confirm that you connected one lead of your meter to pin 4 of the valve under test and the other lead to pin 5 of the valve under test. If you measure to chassis expect to see 0V, 6.3V, 12.6V, 19.9V or 25.2V depending on the valve pin and valve. That's to pins 4, 5 and 9.
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4th Dec 2016, 3:18 pm | #31 |
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Re: Tandberg 64x after changing capacitors
Thanks Graham...maybe I as doing something wrong here....i have removed all the valves. Switched the unit on and did the pin 4 to 5 of the valve socket against each other. When I have done my measurements, I have removed all the valves.
I will do this again and will report... Thank you for your patience and help |
4th Dec 2016, 3:29 pm | #32 |
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Re: Tandberg 64x after changing capacitors
That might explain the problems in making measurements.
Voltage tests need to be done with all the valves plugged in and with mains power applied..
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4th Dec 2016, 3:30 pm | #33 |
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Re: Tandberg 64x after changing capacitors
okay...I have set my voltmeter to 200mV with 20V i could not measure anything...
Its never stays on one measures...always going to minus and plus all the time when i measure the pin 4 and 5 against each other. ECC81s -1 to +1 0,2 to 1,9 ECC83 -1,5 to 0,7 0,1 to 2,1 -1,8 to 0,6 0,4 to 3 ECC82 0,6 to 2,4 -2,2 to 0,9 |
4th Dec 2016, 3:31 pm | #34 |
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Re: Tandberg 64x after changing capacitors
okay...ignore the above then...I have removed all the tubes...
will check again later on today |
4th Dec 2016, 4:41 pm | #35 | |
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Re: Tandberg 64x after changing capacitors
Quote:
Hi Graham, I really appreciate your time and help....really thank you so much. Measured the following on each tubes pins 4-5: ECC83s 12.55V, 12.43V, 13.07V, 13.33V ECC82s 11.86V, 12.24V ECC81s 12.95V, 12.98V Not sure are these within the normal range...the other measurments I have done on pin 1, 7 without the tubes in are they useful? That one ecc83 pin 7 ith 256V worries me (and many other stuff with this too)... Thanks again |
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4th Dec 2016, 4:43 pm | #36 |
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Re: Tandberg 64x after changing capacitors
Those readings are all good!
Now measure the other pins again with the valves plugged in.
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4th Dec 2016, 4:44 pm | #37 |
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Re: Tandberg 64x after changing capacitors
against the chassis for the ground?
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4th Dec 2016, 4:55 pm | #38 |
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Re: Tandberg 64x after changing capacitors
Against the chassis.
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4th Dec 2016, 5:28 pm | #39 |
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Re: Tandberg 64x after changing capacitors
Here it is:
ECC81s 1: 19V 1: 19V 2: 0V 2: 0V 3: 0V 3: 0V 4: 70V 4: 72V 5: 26V 5: 25V 6: 12V 6: 12V 7: 2V 7: 2V 8: 0V 8: 0V 9: 137V 9: 87V ECC82s 1: 18V 1: 19V 2: 29V 2: 31V 3: 6V 3: 6V 4: 196V 4: 191V 5: 25V 5: 25V 6: 13V 6: 13V 7: 1V 7: 1V 8: 0V 8: 0v 9: 52V 9: 42V ECC83s 1: 130V 1: 123V 1:122V 1: 3V (anodes) 2: 0V 2:0V 2: 0V 2: 7V (grids) 3: 1V 3: 1V 3: 1V 3: 2V (cathodes) 4: 0V 4: 0V 4:0V 4: 3V (heaters) 5: 12V 5: 0V 5: 13V 5: 3V (heaters) 6: 136V 6:126V 6: 91V 6: 13V (anodes) 7: 0V 7: 0V 7: 0V 7: 0V (grids) 8: 1V 8: 1V 8: 0V 8: 0V (cathodes) 9: 6V 9: 6V 9: 6V 9: 0V (heater centre taps) I think some of the readings shows something bad...the lastECC83 tube in the row.... Thanks again Graham! |
4th Dec 2016, 5:57 pm | #40 |
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Re: Tandberg 64x after changing capacitors
There's something wrong with your measuring technique here.
The heater voltages are all wrong with respect to the chassis. Instead of measuring with respect to chassis, try measuring with respect to the negative side of one of the capacitors mentioned in post #24.
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