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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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13th Jan 2017, 4:07 pm | #161 |
Dekatron
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Re: Tandberg 64x after changing capacitors
Yes, so far as I can make out, pins 2 are the grids.
Lawrence. |
13th Jan 2017, 4:21 pm | #162 |
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Re: Tandberg 64x after changing capacitors
Okay...
The opposite tube of V5 (not sure is it the V7 or8? ) pin 2 has a very little hum, while the opposite tube of V6 has huge hum, same volume as the pin 7 of the V5. Are these pairs such V5 is a pair of V7 (opposite of each other) and the V6 is pair with V8? |
13th Jan 2017, 4:37 pm | #163 |
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Re: Tandberg 64x after changing capacitors
The valve opposite V5 (ECC83) on the other side of the switch is V7 (ECC82)
The valve opposite V6 (ECC83) on the other side of the switch is V8 (ECC82) Can you confirm again the result of the hum test on pin 2 of V7 and on pin 2 of V8. Lawrence. |
13th Jan 2017, 4:41 pm | #164 |
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Re: Tandberg 64x after changing capacitors
Thanks Lawrence,
V7 pin 2 is very weak hum (same as pin 7 on V6) V8 pin 2 huge hum (exactly the same as pin 7 on V5) The result is like an "X" in terms of similarity between the tubes...none of the opposite tubes of each oother has similar readings but they have in an "X" shape...V5 readings equals of V8 and V6 equals of V7. |
13th Jan 2017, 4:51 pm | #165 |
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Re: Tandberg 64x after changing capacitors
CORRECTION:
V7 has NO hum at all on pin 2. V6 has less hum than the V5 on pin 7. V8 pin 2 has equal hum to V5 on pin 7. Levente |
13th Jan 2017, 4:55 pm | #166 |
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Re: Tandberg 64x after changing capacitors
I have re done the test, and correcting on thing, the V7 has no hum at all on pin 2
V7 has NO hum at all on pin 2. V6 has less hum than the V5 on pin 7. V8 pin 2 has equal hum to V5 on pin 7. Levente |
13th Jan 2017, 5:20 pm | #167 |
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Re: Tandberg 64x after changing capacitors
Ok, the results up to the last test made sense but the last test seems to conflict with those previous tests...Never the less, you can do another hum test, same valves as last time, V7 and V8, this time it's pin 7 on each valve, you might have to turn up the output level control (volume) even further.
Lawrence. |
13th Jan 2017, 5:25 pm | #168 |
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Re: Tandberg 64x after changing capacitors
Okay,
V7 and V8 pin 7 has a very little hum, very high frequency hum but the same on each pin 7. The other "hums" on V5 and V6 ver very loud on my previous test and sounded more like 60 cycles hums. The V7 and V8 hums on pin 7 are much faster, more cycles than 50 or 60....barely hear-able...the V8 hum on pin 2 is a very loud hum, again like a 60 cycles hum...different to the pin 7. Thanks Lawrence! |
13th Jan 2017, 5:34 pm | #169 |
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Re: Tandberg 64x after changing capacitors
This:
"Okay...just tested it The first tube I believe is the V5 pin 7 has huge hum..much louder than the C205 cap had... Th other tube V6 pin 7 has no hum, just a tiny little noise when i touch it for a second...like an electrical tiny little pop, but definitely no hum there at all.." Contradicts this: "The other "hums" on V5 and V6 ver very loud on my previous test and sounded more like 60 cycles hums." Lawrence. |
13th Jan 2017, 5:37 pm | #170 |
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Re: Tandberg 64x after changing capacitors
Yepp...the V6 has a hum on pin 2, pin 7 has no hum.
Sorry i think I got confused on the pin's.... |
13th Jan 2017, 5:41 pm | #171 |
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Re: Tandberg 64x after changing capacitors
I think I am gonna start again measuring the pin 2s and pin 7s on each tubes and report it back
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13th Jan 2017, 5:48 pm | #172 |
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Re: Tandberg 64x after changing capacitors
V5
Pin 2= huge hum Pin 7= huge hum V7 Pin 2= NO hum Pin 7= Barely hear able high frequency hum V6 Pin 2= NO hum Pin 7= Hum, but weaker compare to V5 V8 Pin 2= huge hum pin 7= Barely hear able high frequency hum I hope better this way as I got confused on pin 7 and V7 i think...sorry |
13th Jan 2017, 6:23 pm | #173 |
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Re: Tandberg 64x after changing capacitors
Thanks Lawrence,
All the tubes a lit up visually okay. V5s pin 6 = 126V pin 7 = -0.08V pin 8 = 0 V Thats what i measured just now.... |
13th Jan 2017, 6:44 pm | #174 |
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Re: Tandberg 64x after changing capacitors
I've deleted the last post I made, there was an error in it, I'll post again in a bit, I'm on dish washing and fire lighting duty
Lawrence. |
13th Jan 2017, 6:46 pm | #175 |
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Re: Tandberg 64x after changing capacitors
)) that's okay..thanks man for all the help so far! Levente
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13th Jan 2017, 8:05 pm | #176 |
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Re: Tandberg 64x after changing capacitors
Ok lets eliminate the possibility of one of the playback heads being open circuit or a discontinuity/high resistance in the wiring/connections to them, power off and do a resistance test, a resistance test between chassis and the junction of C205 and R201, then a resistance test between chassis and the junction of C206 and R202.
Lawrence. |
13th Jan 2017, 8:33 pm | #177 |
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Re: Tandberg 64x after changing capacitors
Okay, i have measured the two resistors and both of them are measuring 256 Ohms.
Levente |
14th Jan 2017, 8:19 am | #178 |
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Re: Tandberg 64x after changing capacitors
...on the playback PCB all the capacitors had been changed besides these:
C201 C203 C202 C204 C215 C216 C219 C220 the C 201 and 203 are a brown drop tantalum? or ceramic looking caps, the C 203 and 204 a silvery looking with some pink liquid inside, some styrolfex or polystyrene types? and the rest are Hunts caps, these are also covered with some ceramic hard casing... shall I just go ahead and change all of these? I have removed two resistors out of the pcb to test them and they were gave me OK reading. R201 and R202. I can not remember the exact readings as It as months back, but i've put them back in place. The oscillator board is also full of plystyrene caps, and one big one which I can not see what it is without taking it out..looks like some electrolyt of old Siemens or sthing... i am just really guessing as I am totally lost...damn. Levente |
14th Jan 2017, 10:13 am | #179 | |
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Re: Tandberg 64x after changing capacitors
Quote:
More DC voltage measurements now with respect to chassis, all pins of V5 and all pins of V6, if their heaters are lit up then you don't need to measure pins 4, 5, and 9. Don't change anymore components yet. Lawrence. |
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14th Jan 2017, 10:33 am | #180 |
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Re: Tandberg 64x after changing capacitors
Weird readings....
V5 pin 1: 138V pin 2: -0.64 HUGE buzz when I touch this on my headphone pin 3: 1V pin 4: 0.01V pin 5: 12V pin 6: 130V pin 7: -0.08V pin 8: 0.32V pin 9: 6.63 V V6 pin 1: 128V pin 2: 0V pin 3: 1V pin 4: 0.01V pin 5: 13V pin 6: 96 V pin 7: -0.06V pin 8: 0,6 pin 9: 6.41 V Levente Last edited by Levente; 14th Jan 2017 at 10:39 am. |