hi! thanks for the reply's. dr phil there was a typo. i corrected it.the rectifier i put in is 1000v at 25 amps.the amp works perfectly.just having problems with the pilot light.i already put a new light in and it still doesn't work.the pilot light is an exact replacement for what was in the amp. it is a 2150a1 idi 125vac 1/2 watt.enzo as for the test points i am testing from the chassis ground to each of the leads on the pilot light.i am wondering if the high dc voltage blew out the new pilot light.the ac power comes in on a switch the goes thru a 1k heat sinked resistor. then it goes to the center terminal of a triac. mac15a6. from there not sure what happening with it. i get 124v ac on both sides of the heat sink resistor.thought that was strange and the triac reads 124v ac on all 3 legs.the leads from the pilot light go as follows: i don't have a schematic so bear with me.the lead farthest from the switch (120v/240v switch)goes to one side of a resistor. to the - leg af a 330uf 200v electrolytic.then goes to the minus leg of the 4pin 1000v 25 amp bridge rectifier.the other wire of the pilot goes to a reisistor that t's off into 2 more resistors with the top resistor going to the + leg of another 330uf 200v electrolytic.then it ends on the + side of the bridge rectifier.another words both pilot light lead circuits terminate on the outside legs of the 4pin bridge rectifier.i tested the resistors and the all seem ok.this amp is a hair puller for a rookie.i also tested for ac on both wires of the pilot light and got no ac reading.it just reads dc voltage ...thanks phil and enzo for helping me with this. i'm close,but not there yet on fixing this moose.....ed

i have 166.3 vollts dc on one terminal of the light and -163 dc on the other. the light is 125volt ac.any ideas. i must have something leaking dc into it. there are no identifiers for dirrection with the caps.i have replaced all the large capacitors and the bridge rectifier with a 1000volt 25 amp part. the amp works fine,but no pilot light.i have another post with pictures of the circuit board if it helps....thank any help apreciated......ed

got the amp working ,but the power light doesn't work.i replaced the light which is 125volt ac. when i test the board where the leads attach the board i get 166 volts dc and -163.6 volts.i don't get any ac voltage.something seems to be leaking dc into this part of the circuit. any ideas?...thanks...ed!

i learned something about rectifiers.they have an angle on one side or the other to designate polarity.i replaced a couple of capacitors along with the rectifier.the rectifier i replaced the original with is a 1000volt 25 amp.the amp now plays,but i have a bad neon light.next week i'll receive the new light from jameco electronics.will let you know how i make out.i have to remove a clip that holds the neon light in place kind of a pain to get at....later...ed

the 3 caps i replaced on mine were on the right hand side of your board.there is a group of 5 near the bottom right side of the board. i replaced the 3 in the middle of the group of 5.another words all of them except the top and bottom cap.hope yours is the same...hope it works for you.i know it could be another cap somewhere,but thats what fixed the one i repaired.luckily it was a cheap fix. they wanted $300.00 at a roland service center they were going to replace the whole board ouch!!.i got it after they looked at it from a friend. i made his day as i was alot cheaper for me to fix it.saved him alot of bucks.....!!!....ed

ps: don't forget to look for bulged tops on all your caps if you find any replace them.the ones i replaced looked good but at least one of the 3 was bad...

sorry i didn't see your posting.if you send a picture of the board it might jog my memory of what i replaced.hopefully it is the same capacitor that is bad.i injected a  sine wave signal into a cap at the top right hand side of the board and then i checked the wave forms from the output  back up towards the origin of the injected signal till i got a good signal. then i replaced 3 caps on the right side of the board that were grouped together.after i replaced the caps . i got a perfect square wave out the ouput while injecting a sine wave.hope this helps.i have a good preamp board for a roland here at the house,the problem with the hiss was not on the preamp input board..hope this helps a little. like i say if i see a picture of the board i might better be able to dial you in on the caps i replaced.....ed

p.s the capacitors i replaced were  all electrolytics.non polarized capacitors seldom go bad!.....
also look at the tops of the capacitors for bulged tops or leakage.

thanks for the input! once i get it out of the board;it's  fighting me,i'll see if there are any markings imbossed on the rectifier down near the chip legs. the rest of the chip has been sanded,so that people like you and me have to guess at what it is.seems like the secretive building could work both ways for the builder.someone might find out that they are going to have problems repairing it down the road, so they will buy a simular item that will be easy to maintain if broken.....thanks....ed!!

i'm answering my own question.could this be a rectifier bridge?it has 4 legs. if this is so. i should be able to use a 400v 4amp bridge rectifier as the capacitors are rated at 400 volts...any suggestions of ideas from the pros? thanks...ed!

i have no power to either leg of the top right capacitor in picture #13.it ties in with the 4 leg part with the heat sink to the right of the top right capacitor.i notice also one of the traces of the part is connected to the led which is not working.again no part numbers on the part.i believe its part of the power supply.switching regulator?not sure what is is or what to replace it with. it has 167 volts going to one of its legs.....help!!!! thanks...ed!!

one for the gipper! for all you that want to test electrolytic capacitors out of circuit,but don't have money to spend on a expensive cap meter you can make your own cheap.take a 9 volt battery connector and solder a set of alligator leads or ic connectors; whatever you choice may be.then hook a 9 volt battery to the connector.connect the battery leads to the electrolytic cap observing polarity.now hook a dc volt meter across the capacitor also observing polarity again.the meter will read the 9 volt battery voltage.then disconnect one of the battery alligator clips and the voltage will drop off. if the voltage drops to zero in a second or 2 the cap is bad.the voltage should bleed of slowly.this does the same thing as many high dollar cap testers.my sencore cap tester does the same thing.you can make one for abot a buck, so why not make a couple......later....ed

will do....ed

just fixed a  hp vs17e  computer monitor.it had 3 bad electrolytics in the power supply(monitor was dead). the only way i could tell is they were bulged on their tops.they tested good out of circuit with a $200.00 esr meter.i took a regular capacitance meter and 2 read about 309uf and 1 measured 820uf.i'm guessing out of circuit a capacitance meter gives a pretty good indication if an electrolytic is bad.this was my first monitor repair.guess it's pretty hard to know for sure whats bad and what good in circuit...later...ed

got the schematic for this amp.i have analog signal coming into the cs4221-ks chip ,but no analog coming out. i just got a replacement chip for it .i will let you know how it plays out....ed!!!!

hey scooperman.got my cs4221-ks chips today.i got 3. if you have a problem getting one let me know.i could send one to you if you are in the usa and in dire need of one.....will update the results of it's replacement in my other posting on the johnson mirage amp with no analog output form this chip....ed

i got analog signal into  both the left and right channels of the cs4221-ks ,but got no signal from the left and right analog outputs,so i have come to the same conclusion.that i have a bad chip.be it a sine wave or an audio signal it should pass signal.as you said the rest of the digital is another story.when i found no audio out i didn't worry about any of the digital part of the chip. i just concidered it dead in the water.....ed