pucho812
Well-known member
Below is half the schemo of a Console PSU power supply. It's on arrived on my bench as the 160 left sounding good. The problem is the unit does not send out +24V. This is not good as +24V controls logic switching and Lights. The owner could give to shytes about the lights but the console logic is another story. Can't run it without it. The PSU is simple in design and each rail has it's own traces seperate from the other rails on a single PCB. The unit was powered down by the owner to do console maintanence swaping out some switches. When powering back up the +24V Led would not light this indicating a problem, PSU was not outputing +24.
In steps me. I ran it without load and it was a no go on the +24. I have tested as much as I can(caps resistors and diodes). They all test out I.E. seem to work as normal. There are no test points on said PSU. screw you Sony... :razz: The maintenance manual only lists parts that are possible subject to fail under normal operation conditions. This rules out the PSU trafo which is huge. So this leaves me down to parts Q6, Q2 both which are transistors, tip29A and parts u3 and u2. U3 is a motorola MC1723CP which is a voltage regulator IC. and U2 is a motorla Lm358N A DUAL DIFFERENTIAL INPUT OPERATIONAL AMPLIFIERS. What are the odds of these 4 componants failing. I am kind of out of ideas.
Any suggestions other then replacing the 4 componants to see if that fixes the problem. I have this suspecion that due to age the parts failed. The PSU is over 10 years and has never had maintanence on it until now.
EDIT: forgot to mention that the fuse for that section of the board works fine, tests out and ran another PSU.
In steps me. I ran it without load and it was a no go on the +24. I have tested as much as I can(caps resistors and diodes). They all test out I.E. seem to work as normal. There are no test points on said PSU. screw you Sony... :razz: The maintenance manual only lists parts that are possible subject to fail under normal operation conditions. This rules out the PSU trafo which is huge. So this leaves me down to parts Q6, Q2 both which are transistors, tip29A and parts u3 and u2. U3 is a motorola MC1723CP which is a voltage regulator IC. and U2 is a motorla Lm358N A DUAL DIFFERENTIAL INPUT OPERATIONAL AMPLIFIERS. What are the odds of these 4 componants failing. I am kind of out of ideas.
Any suggestions other then replacing the 4 componants to see if that fixes the problem. I have this suspecion that due to age the parts failed. The PSU is over 10 years and has never had maintanence on it until now.
EDIT: forgot to mention that the fuse for that section of the board works fine, tests out and ran another PSU.