nashou
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Post by nashou on Dec 6, 2016 23:26:42 GMT -5
They are both 22.55
It changed slightly afer warming up more from 22.60 both.
Nashou
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Post by mastertech on Dec 6, 2016 23:32:07 GMT -5
What are the B+ and B- voltages?
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nashou
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Post by nashou on Dec 6, 2016 23:33:07 GMT -5
And on the blank pads of the two removed resistors I get similar reading on both sides .
the two sides are the same as above and the other pads are -.645 for both.
nashou
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nashou
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Post by nashou on Dec 6, 2016 23:34:18 GMT -5
What are the B+ and B- voltages? - 25.13 and + 25.18 they move up and down a little maybe about .05 to .15 |
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Post by mastertech on Dec 6, 2016 23:39:09 GMT -5
So we went from to much - voltage to to much + voltage by changing the power supply. What do you have the current set at?
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nashou
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Post by nashou on Dec 6, 2016 23:45:08 GMT -5
I have it set to the low setting switch and on the lower markings on the meter it is less then the .1 maybe .05 marking with the CV light on but the PS switches from time to time where it goes to the C.C light and the amps rise to over the .1 reading mid point of .2 so .15
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Post by mastertech on Dec 6, 2016 23:47:51 GMT -5
Well we have some more thinking to do. I am off to bed.  |
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nashou
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Post by nashou on Dec 6, 2016 23:49:43 GMT -5
TR108 Gate on the outside section has -.456 volts on it compared to TR107 - 345 mV . Big difference I think
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nashou
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Post by nashou on Dec 8, 2016 14:30:36 GMT -5
I been looking up how to measure Current and I was doing it all wrong. So, what I plan to do is to measure the current of each channel at the board input and then the current out of the
servo amp section through R160 and R 161 .
What do you think Mac?
Also the main amp board has a lot of the famous Corrosive glue that they used in the 70-80's that eats at the boards and parts , and all around those big caps on the main board are jumpers and diodes
that are corroded pretty bad. I'll go in and clean that up and inspect that board really well, maybe check the caps etc , then get back to the Eq board.
Athanasios
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Post by mastertech on Dec 8, 2016 15:51:20 GMT -5
At this point anything is worth a try. |
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nashou
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Post by nashou on Dec 8, 2016 17:00:58 GMT -5
At this point anything is worth a try. Ok I am using a Commercial Electric MS8232B Meter. From what I read using other meters, I didn't look this one up specifically , I am suppose to put the leads in circuit to read current. So I unplugged the +/- B connector and clamped one probe to the Connector and the other probe to the jack on the EQ board that corresponds to the voltage I am measuring. So if this is the right method I get 8.25 mA on the - voltage and 5.69 mA on the + voltage. But when I do this and use another DMM to measure the voltage while the other meter in in circuit I get hardly any voltage on the corresponding line. like 1 volt. Not sure if this is normal or if there is another way to measure the current. Athansios |
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nashou
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Post by nashou on Dec 8, 2016 23:06:50 GMT -5
Here is the Amp board. It is a corroded mess in some areas. Also one of the large 7500uf caps measures about 6900 the rest are over 7100uf. I also noticed that TR 343 broke a trace underneath that I had to repair. It might have not been making a very good connection. But this is the negative TR I believe. I'll clean up the Glue and measure the resistors and check all jumpers that might have been compromised by the corrosion. The glue near the TR's that power the EQ board is much more burnt compared to the other Large cap glue. I wonder if those caps were getting hot too and if they help power that +/- B1 line The Pics.     Denatured alcohol is not cutting it, I think I need to use acetone here. |
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Post by mastertech on Dec 9, 2016 16:04:15 GMT -5
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nashou
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Post by nashou on Dec 9, 2016 19:06:24 GMT -5
Thanks Mac. But it seems to be working ok, or isn't it? Nashou |
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Post by mastertech on Dec 9, 2016 19:16:37 GMT -5
That was just in case you ever need it.
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