Thanks all for your input, all good advice. Just had my surgery and all went well so looks like I will be starting the re-cap sometime next week. Have received all the caps, I decided to replace all the axial with radial since they were more common and much less on costs. It will take a...
Hi Harald: Yes the readings are with the amp connected and sending a tone through the system. Measured my house voltage and it was 117 volts ac.
I will redo the measurements after I have replaced all the caps and see what that gives me for voltage into the other voltage distribution points...
I am going to replace all the electrolytic capacitors, I am just trying to get them right now. I had placed an order with SRI and their website indicated that they had them all in stock but then I get an email from them saying they had none of the 18 different caps in stock but they had another...
Theory question, if anyone would like to put in their thoughts. I have been out of the electronics world for a while now and my memory fails me on the following. On the attached drawing there are 2 transistors Q119 and Q121 which is marked as a differential preamp. The signal comes in through...
Sorry I do not understand your response. You had given the transistor number for the one. (480058A is supposed to be a 2N3055) but I did not see a link for the MJ2955. Did I miss something?
Still trying to find out what MJ2955 is or a substitute number. It is a Motorola Transistor but have not made any headway in finding a replacement.
Anyone out there can can shed so light on this for me by chance?? Schematic is attached above
Thanks
OK: Firstly the transistor that is listed as Q22 is actually Q122, along with Q 124 and Q125 are all 3 Numbered RCA 489958A, Transistor Q123 is the only MJ2955. Q119 and Q 121 are both 135 on the top line and underneath says 44H, Q120 has numbers: TI 7315 and EP1125 underneath the first line.
I can give you two examples of the power transistors I am currently looking to find a replacement/substitution for: Following is the numbers and symbols both in TOS cases: 1) the symbol is a sprawled out M, the number is MJ2955 and under that is the number 8026 which I think may be some kind...
That's kind of what I thought it might be. I will get into it and actually measure it when I get to that portion. Still going through the schematics and finding where all the parts are located. Lots of wires...lol... Reminds me of a hammond organ I tried to fix back in the mid 70's
That was my thoughts also. Going to replace all the Electrolytic caps and then work my way into the Tone Generator. The diode's I was referring to is on another sheet. It looks like 2 diodes that are fastened together in series. I am familiar with the diode bridge configuration so thanks for...
I am going to replace all the caps in the system. There are a few hundred...lol.. The tone generator is full of them. They all have some kind of leakage so will probably replace them with the orange style. They are not electrolytic, just regular radial caps, with lots of white dust and...
I have gotten myself into a 1975 Cordovox accordion with a separate amplifier and Tone cabinet. Fortunately I have finally acquired the complete schematics, unfortunately they have just the part numbers from Cordovox. I am trying to find out how to decipher, what a current or substitute part...