KX1200.1 in repair

[Perry Babin]

With the black probe on the point where you connected the jumper, what is the DC voltage on pins 9 and 11 of U14?

 

[Kleinteich2]

pin 9- 11.68v

pin 11- 11.67v

 

[Perry Babin]

Please don't use a hyphen as a separator. In can be taken to mean negative. This is covered on the basic repair page (which you should read now if you haven't done so already).

With the black probe on pin 10 and the red probe on pin 14, what DC voltage to you read?

 

[Kleinteich2]

Please don't use a hyphen as a separator. In can be taken to mean negative. This is covered on the basic repair page (which you should read now if you haven't done so already).

With the black probe on pin 10 and the red probe on pin 14, what DC voltage to you read?

\
i have read the repair guide a few times. this isnt my first repair and i just about read your repair guide everytime i fix an amp.

i will remamber not to use them again. srry. newb mistake.

and i will have to check them tomorrow morning when i get to the shop. does it start to seem as if the lm361 is bad?

 

[Perry Babin]

Until you stated that you had 12v on pins 9 and 11, it seemed likely but that voltage is very far off of what it should be so there may be multiple problems. I need the voltage across pins 10 and 14 to see what the total voltage is on the logic side of the IC.

 

[Kleinteich2]

the highest it got on my meter was .98v dc. but it drops back off when it pulses power protect. on my meter it read 0.2v, 0.5v, 0.98v. then it drops into protect. this all happens in about two seconds. and then it repeats itself.

 

[Perry Babin]

What is the DC voltage with the black probe on the amp ground terminal and the red probe on the negative speaker terminal?

 

[Kleinteich2]

What is the DC voltage with the black probe on the amp ground terminal and the red probe on the negative speaker terminal?

with it cycling in and out of protect?

 

[Kleinteich2]

the highest reading i got was 0.4vdc.

 

[Kleinteich2]

someone before me. worked on this amp and there is a resistor marked 433 jumping from the base of Q144 to resistor R230.. any idea why they did this?

 

[Perry Babin]

That resistor has been on amps that I've seen so it's likely a factory mod.

Is it still producing about 20v on the output filter inductor?

 

[Kleinteich2]

That resistor has been on amps that I've seen so it's likely a factory mod.

Is it still producing about 20v on the output filter inductor?

yes.. i also removed the fast recovery diodes and now i can actualy read the rail voltage on both sides. but i get no power at the other end of the board because of that. it seems as if everything on the power supply side is good.

with those out it does not cycle in and out of protect.

 

[Perry Babin]

Which diodes?

 

[Kleinteich2]

D12,D13,D14,D15

 

[Perry Babin]

What are you referring to as 'rail' voltage? With those out of the circuit, the rail voltage isn't being produced.

 

[Kleinteich2]

ac voltage.

i cant read any thing steady with the amp swinging from power to protect. with these out i could read everything on the power supply.

 

[Perry Babin]

Is it producing both positive and negative 15v on the power supply pins of the various op-amps?

 

[Kleinteich2]

Is it producing both positive and negative 15v on the power supply pins of the various op-amps?

no.just positive +12vdc and +44.34vac. i havnt found a negative ac circuit yet with my dmm.

 

[Perry Babin]

What are the numbers on the components just beyond the rectifiers that you removed?

 

[Kleinteich2]

two of YG225N2
and two YG2252.

i believe these are what your asking for?