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Diode 070-030 for Mcintosh 2505

cuthien

cuthien

Active Member
In the service manual for 2505 (older version), it has a section talking about a modification to replace some resistors/caps with different value and add in a diode 070-030 in the circuit to improve power output. Does anyone know what is the value for this diode is. It said diode part# 070-030. Thanks.
 

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Tell everyone the DXXX id on the schematic and sorta where it is (driver board, power supply). The schematic I have doesn't list part #'s.

Murray
 
skippy_ps said:
Tell everyone the DXXX id on the schematic and sorta where it is (driver board, power supply). The schematic I have doesn't list part #'s.

Murray
Click to expand...

Here it is. It's near the c33 can cap.
 

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1N4002 (100 V) should work fine there. The problem is, I don't know what side the cathode is on those old style pointy diodes. Perhaps one of the other guys will know.

Murray
 
Ok, I finally found this on the schematic - power supply. There is (about) 82 V there so probably should go to 1N4003 (200 V). My schematic is the old style like your amp and it doesn't show this mod so it's be better if someone could figure out which way the cathode is on that added diode.

Murray
 
skippy_ps said:
Ok, I finally found this on the schematic - power supply. There is (about) 82 V there so probably should go to 1N4003 (200 V). My schematic is the old style like your amp and it doesn't show this mod so it's be better if someone could figure out which way the cathode is on that added diode.

Murray
Click to expand...

Thanks for the value of the diode. Now, which way do i install it is the question heh.

Do you need this intruction to mod your amp? I can send you a pdf copy. Actually i will just put it here for everyone to see. I will upload shortly.
 
Instruction to upgrade older Mac 2505 serial # 10K01 through 11K54 to improve power handling.
 

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I asked Terry Dewick and he says that the "pointed" end is the same as the banded end (cathode) on a, umm, regular diode. Kinda makes sense too.

Murray
 
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