My CD 63 KI will be done for me when the 3TX and servo regs are done.Its never donetill the next mod trust me its an obsession
alan
I may do others just for kicks.
I really want upgrade my amp, A PM7001 KI.
Exactly the same inside as a PM8300 i'm told.
After that we'll see.
Q106 overheat
Hi
I was doing some cleanup in my player, shortening wires etc.
When I put the player together, it doesn't work anymore. The tray goes in and out but doesn't read discs.
Q106 gets burning hot
, so I figure the problem lies around there.
I measured voltages on the pins. They all measure normal except pins 1 and 8.
On pin1 is -6.4v (should be 0v), on pin8 is -0.5v (should be 2.5v).
I guess I have fried something by mistake.
Any ideas?
Hi
I was doing some cleanup in my player, shortening wires etc.
When I put the player together, it doesn't work anymore. The tray goes in and out but doesn't read discs.
Q106 gets burning hot
, so I figure the problem lies around there.I measured voltages on the pins. They all measure normal except pins 1 and 8.
On pin1 is -6.4v (should be 0v), on pin8 is -0.5v (should be 2.5v).
I guess I have fried something by mistake.
Any ideas?
See if you can measure a low resistance or short from the output of Q106. If not then you will have to isolate the items it feeds one at a time to see where the large current flow is heading.
Are you sure you haven't connected any of those shortened wires incorrectly.
Hi
I was doing some cleanup in my player, shortening wires etc.
When I put the player together, it doesn't work anymore. The tray goes in and out but doesn't read discs.
Q106 gets burning hot
I measured voltages on the pins. They all measure normal except pins 1 and 8.
On pin1 is -6.4v (should be 0v), on pin8 is -0.5v (should be 2.5v).
I guess I have fried something by mistake.
Any ideas?
Try shorting pin 7 to 8. They are both inputs, so that will do no harm. Is pin 1 still -6.4V? Then your driver is probably broken.
Would that be the LM317 with a gyrator in front of it?
I found a post of the 'Super-Raygulator' here
Thank you Ray
I am planning something like it to feed 18v to an opamp.... what would you recommend for vref ?
Are there any 18v low noise zeners ?
Strange...now pin1 and pin8 measure correctly. But pin3 and pin5 are way off. The other op-amp in IC.
Pin 3 measures +6v (should be 0v) and pin 5 measures +5.5v ( should be 2.5v).
Capacitor fault.....hmmmm?
Would that be the LM317 with a gyrator in front of it?
I found a post of the 'Super-Raygulator' here
That's a long time ago
Check if the 2.5V reference voltage is stable, it is made with two resistors off the 5V supply. This is present on one of the inputs of each driver. Other cause could be one of the supplies failing because of the crack in a PCB trace.
That's a long time ago
Yes, indeed
But it's still alive!
Ray
Yes, the VREF voltage is pretty stable 2.5 volts at R143 and R144.
Measured resistors around Q106 and they all seem to be OK. I also unsoldered and measured some of the small capacitors around Q106, but found nothing obvious.
Is it safe to swap Q106 and Q105, to check if it's Q106 that's faulty?
Presumably you could use some lower voltage zeners in series? I think I did that once.
Pete
Yep, it's now obvious Q106 has blown.
I swapped Q06 and Q105. The same IC, now in Q105 socket, gets burning hot and the sled motor went mental.
Mouser has them still in stock:
TCA0372DP2G ON Semiconductor | Mouser
Possible causes why Q106 faulted:
Wire/solder residues shortening pins.
Removing/nudging of the ribbon cable between Main PCB and Mech.
That ribbon flat cable doesn't look very high-class.
Does anybody know of a better replacement, that fits in the cable connectors?
Maybe gold-plated or something....
I blew one of these ICs when I carried out one of the 10 modifications. Mine was worse than yours as I could see spark and explode sound when I switched on the CDP
I also mentioned this happening in this forum sometime ago. Later I found an unnoticeable short circuit by remaining solders being left behind. After that I always use contact cleaner to clean up the PCB and check by a magnifying glass before switching on.Try eBay for the IC as it will be cheaper.