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| grundig 1070 https://www.dampfradioforum.de/viewtopic.php?f=2&t=30223 |
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| Autor: | inecik [ Di Mär 24, 2020 14:16 ] |
| Betreff des Beitrags: | grundig 1070 |
hi everyone I have repair a grundig K2musiktruhe(same machine with 1070).I hope , you will help me. the radio now playing but not perfect.I have replaced all paper capacitor, but there are 280VDC on pin 9 in EABC80 tube. |
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| Autor: | Radio Martin [ Di Mär 24, 2020 14:25 ] |
| Betreff des Beitrags: | Re: grundig 1070 |
Hi, At first i'll place the Schematic: https://nvhrbiblio.nl/schema/Grundig_1070.pdf Pin 9 is the Anode of the Triode System and they should be around 70V You should measure the Resistors R30 and R31, These two Resistors are conected to the Anode of the EABC80 and going to Aode Voltage. I think during the Change you have bridget them (Maybe soldered a capacitor to the wrong connector). They should have a Resistance around 440k Ohms. |
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| Autor: | inecik [ Di Mär 24, 2020 14:37 ] |
| Betreff des Beitrags: | Re: grundig 1070 |
Radio Martin hat geschrieben: Hi, At first i'll place the Schematic: https://nvhrbiblio.nl/schema/Grundig_1070.pdf Pin 9 is the Anode of the Triode System and they should be around 70V You should measure the Resistors R30 and R31, These two Resistors are conected to the Anode of the EABC80 and going to Aode Voltage. I think during the Change you have bridget them (Maybe soldered a capacitor to the wrong connector). They should have a Resistance around 440k Ohms. hi,I measumend thats resistors and 220K resistance, just now |
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| Autor: | Radio Martin [ Di Mär 24, 2020 14:48 ] |
| Betreff des Beitrags: | Re: grundig 1070 |
Both of them 220k? To be honest, i'm not sure if the R30 is a 220K, because in the schematic stands 220A, but that could be a Print mistake. can you look which Value is printed on the Resistor? Can you measure the Voltage directly behind the Rectifier and on Pin 9 of the EL84? At the Rectifier there should be 280V and on the G2 from the EL84 I think around 270V |
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| Autor: | inecik [ Di Mär 24, 2020 14:56 ] |
| Betreff des Beitrags: | Re: grundig 1070 |
Radio Martin hat geschrieben: Both of them 220k? To be honest, i'm not sure if the R30 is a 220K, because in the schematic stands 220A, but that could be a Print mistake. can you look which Value is printed on the Resistor? Can you measure the Voltage directly behind the Rectifier and on Pin 9 of the EL84? At the Rectifier there should be 280V and on the G2 from the EL84 I think around 270V the rectifier(+) is 295VDC EL84 pin 9 is 274VDC |
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| Autor: | Radio Martin [ Di Mär 24, 2020 15:01 ] |
| Betreff des Beitrags: | Re: grundig 1070 |
That sounds ok But that means, that the Resistors don't have Resistance, because you have the same Voltage at both sides of the Resistors . Pin 9 EL84 is on Anode Voltage like the Resistors to Pin 9 of EABC80. Please measure the Resistance between this two Points (pin 9 EL to pin 9 EABC) |
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| Autor: | inecik [ Di Mär 24, 2020 15:08 ] |
| Betreff des Beitrags: | Re: grundig 1070 |
Radio Martin hat geschrieben: That sounds ok But that means, that the Resistors don't have Resistance, because you have the same Voltage at both sides of the Resistors . Pin 9 EL84 is on Anode Voltage like the Resistors to Pin 9 of EABC80. Please measure the Resistance between this two Points (pin 9 EL to pin 9 EABC) 0.46M ohm between pin9 EL84 to pin9 EABC80 |
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| Autor: | Radio Martin [ Di Mär 24, 2020 15:13 ] |
| Betreff des Beitrags: | Re: grundig 1070 |
Okay, that's weird… Try to disconnect the Capacitor from Pin 9 EABC and measure the Voltage again, Maybe measure the Voltage of the Resistors. |
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| Autor: | inecik [ Di Mär 24, 2020 15:21 ] |
| Betreff des Beitrags: | Re: grundig 1070 |
Radio Martin hat geschrieben: Okay, that's weird… Try to disconnect the Capacitor from Pin 9 EABC and measure the Voltage again, Maybe measure the Voltage of the Resistors. is it 10 nano farad |
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| Autor: | Radio Martin [ Di Mär 24, 2020 15:31 ] |
| Betreff des Beitrags: | Re: grundig 1070 |
Yes, just dissolder this capacitor and make sure it wont get Connection to enything else while the Radio is on. Then Measure the Voltage again. I don't think this would be the Problem, but you never know. Often the Problems are just so simpel that you search Hours at the wrong Point. |
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| Autor: | inecik [ Di Mär 24, 2020 15:39 ] |
| Betreff des Beitrags: | Re: grundig 1070 |
Radio Martin hat geschrieben: Yes, just dissolder this capacitor and make sure it wont get Connection to enything else while the Radio is on. Then Measure the Voltage again. I don't think this would be the Problem, but you never know. Often the Problems are just so simpel that you search Hours at the wrong Point. I disconnected 10 nanof cap. and measuremend voltage on pin9 (eabc80) 265VDC |
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| Autor: | Radio Martin [ Di Mär 24, 2020 15:42 ] |
| Betreff des Beitrags: | Re: grundig 1070 |
ok and there is Nothing else connected then the resistors? can you measure the voltage from the other side of the resistors? This than this should be 274V like on pin 9 of he EL84 |
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| Autor: | inecik [ Di Mär 24, 2020 15:48 ] |
| Betreff des Beitrags: | Re: grundig 1070 |
Radio Martin hat geschrieben: ok and there is Nothing else connected then the resistors? can you measure the voltage from the other side of the resistors? This than this should be 274V like on pin 9 of he EL84 other side of resistors??? |
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| Autor: | Radio Martin [ Di Mär 24, 2020 15:52 ] |
| Betreff des Beitrags: | Re: grundig 1070 |
Yeah, you have measured at the Pin9 of the EABC, there is 265V. Now pleas measure the Voltage at the other end of the resistors, there should be 274V |
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| Autor: | inecik [ Di Mär 24, 2020 15:55 ] |
| Betreff des Beitrags: | Re: grundig 1070 |
Radio Martin hat geschrieben: Yeah, you have measured at the Pin9 of the EABC, there is 265V. Now pleas measure the Voltage at the other end of the resistors, there should be 274V it is 272VDC |
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