Well diagnosed :-D Using identical diodes gives it a good chance . Ive never seen one of those noise makers before. There is a bloke that repairs tv sets and they have diodes in parallel in the psu. Yep the one doing more work goes short and stops the set dead. I think a clip on heatsink would slow there death down a bit lol.
On the main power board you replaced the diodes on, there is a light blue box which has 2 pins underneath and that is a type of fuse if you did'nt know as I am working on the same cd player which is my brother in laws here in Great Britain. He told me that his just went of and I checked the capacitors to see if any was blown but no and I couldn't find any else what is the problem but I will check them 2 diodes and replace them if faulty. Many thanks for your help. Take care Yours Faithfully. Paul Brown
Thanks for the video! Btw, how about the buttons issue? My Sony cmt-s40d has an issue. The device's remote works, but the buttons on the device itself don't. Can you tell me what the problem is?
Hi. I just have a small reminder that the 1N5822 diode is for 40V, not 20V. At least according to what I found on the store's website. But it shouldn't affect the function, right?
hi there, i appreciate your work and explanation procedure... i am having the exact problem as yours... My son powered off the device with the power buttton and when (right after) i tried to power it on.. dead.. I opened the package but the short it seems to be on the main board (0.3 ohms to power supply, 0 ohms on main board). Where should i look? any advice please. Thanx for your time!
So you unplug power supply and only short on main board? I would say connect an external bench supply to the board and limit to 1 Amp if possible. Look/ feel around for what is getting hot. Hopefully a surface mount capacitor or something. If nothing then increase current but don't let it exceed normal supply voltage.
@@JonnyFix hi again! i followed your steps once again... no volts - 0,2 ohms on power board connector connected to the main board- and the exact place ( the yellow one) you mentioned is hotter than anything else one the power and main board, which are normal cool! i removes the two diodes you mentioned and the one had contuinity but the other not! I hope tha replacing the diodes will solve the problem for me! i will let you no! thanx again!
Great video. Thank's a lot! Could somebody tell me why two diods in parallel are required? I mean the whole device is not using more than 24W. So the 3A per one diode should be fine. Or am I wrong? The thing is I found the failing diode, but don't have a spare. I powered up (without speakers) for a short test with only one diode it it seems to work fine.
May be load sharing for longevity. I think it also has an amp to feed speakers so perhaps in case there's surges from those thumping bass notes they have to keep up with :)
Very useful video ! I have the same radio and the same problem. Unfortunately the power board produces 12V correctly, so most probably there is an error on the main board. I have managed to find the official repair guide for this radio. But it is useless as it only contains logic to rule out which board is faulty and instructs to change the board. All I can do is to check the electrolite condensators and the diodes on the main board. Do you have any ideas what to do if all the condensators and diodes are OK ?
At 5:27 you can see just to the right of where the power supply connects to the main board there's chip beside a black round inductor and some caps, that is a regulator and you will want to check there is some kind of normal voltage there like 3 or 5 (I don't know what it should be). Also the white flex and other wires that go to the front panel see if they printed on the PCB what each pin is and if there's a mention of voltage test to see that's present. If one is missing follow the traces back to the source and look for bad components or a short. If all voltages seem present and correct maybe it's brain dead. Check power button has a voltage on one pin that is pulled to ground when pressed, often this is sourced from the processor so if missing maybe processor has no power or hasn't booted. Using a scope check there's a clock signal on the main processor (big chip in middle, look for datasheet for pinout), also check reset pin isn't active for some reason. If clock and reset ok look for an eeprom chip and use scope on data lines to see if it's reading it at plug in and/or when you push power button. Many things you can test for to try figure out what part isn't working, hopefully that gives some direction!
*_You sound like a fellow Kiwi... We should never underestimate the ability of a Kiwi, as isolated as we may be, to fix any problem, be it fixing a piece of broken farm machinery or splitting the ATOM*_.
Sir i have a sony cmt sbt20 my problem is system is good working but I have press equalizer button flat pop and other or mega bass button the bass down low bass and restart the system bass is generally works good Please tell me what js problem
First, take out the rear metal plate. Just pop out the bottom metal clips with a flat screwdriver and you can slide it up. After that, you can find a big white plastic gear on the bottom of the CD player. Use your finger to turn it until the mechanism pushes out the CD tray. After that, you can take the silver front plastic cover from the tray, four clips are holding it. After that, you can use the same mechanism to close the tray. Now you can take the CD player out.
Well diagnosed :-D Using identical diodes gives it a good chance .
Ive never seen one of those noise makers before.
There is a bloke that repairs tv sets and they have diodes in parallel in the psu.
Yep the one doing more work goes short and stops the set dead.
I think a clip on heatsink would slow there death down a bit lol.
On the main power board you replaced the diodes on, there is a light blue box which has 2 pins underneath and that is a type of fuse if you did'nt know as I am working on the same cd player which is my brother in laws here in Great Britain. He told me that his just went of and I checked the capacitors to see if any was blown but no and I couldn't find any else what is the problem but I will check them 2 diodes and replace them if faulty. Many thanks for your help. Take care
Yours Faithfully.
Paul Brown
Good job Jonny!
i have one of these units, one of the speakers stops working after some time , any ideas for an easy fix or any safe way to use a different speaker ?
i have one like this, also damaged power supply board. just replaced with Dell laptop adapter charger last night, it works well now.
Nothing wrong with a little re-purposing and substitution!
Thanks for the video! Btw, how about the buttons issue? My Sony cmt-s40d has an issue. The device's remote works, but the buttons on the device itself don't. Can you tell me what the problem is?
Where can I get repair of my radio
It’s funny how common blown schottky diodes are on switching supplies, I’ve come across that many times.
Yet on a little system like this they were well over-rated for the job and you'd think would never fail, if well manufactured to those specs.
Hi. I just have a small reminder that the 1N5822 diode is for 40V, not 20V. At least according to what I found on the store's website. But it shouldn't affect the function, right?
Right, it's not a problem
hi there, i appreciate your work and explanation procedure...
i am having the exact problem as yours... My son powered off the device with the power buttton and when (right after) i tried to power it on.. dead.. I opened the package but the short it seems to be on the main board (0.3 ohms to power supply, 0 ohms on main board). Where should i look? any advice please. Thanx for your time!
So you unplug power supply and only short on main board? I would say connect an external bench supply to the board and limit to 1 Amp if possible. Look/ feel around for what is getting hot. Hopefully a surface mount capacitor or something. If nothing then increase current but don't let it exceed normal supply voltage.
@@JonnyFix hi again! i followed your steps once again... no volts - 0,2 ohms on power board connector connected to the main board- and the exact place ( the yellow one) you mentioned is hotter than anything else one the power and main board, which are normal cool! i removes the two diodes you mentioned and the one had contuinity but the other not! I hope tha replacing the diodes will solve the problem for me! i will let you no! thanx again!
Great video. Thank's a lot! Could somebody tell me why two diods in parallel are required? I mean the whole device is not using more than 24W. So the 3A per one diode should be fine. Or am I wrong? The thing is I found the failing diode, but don't have a spare. I powered up (without speakers) for a short test with only one diode it it seems to work fine.
May be load sharing for longevity. I think it also has an amp to feed speakers so perhaps in case there's surges from those thumping bass notes they have to keep up with :)
Very useful video ! I have the same radio and the same problem. Unfortunately the power board produces 12V correctly, so most probably there is an error on the main board. I have managed to find the official repair guide for this radio. But it is useless as it only contains logic to rule out which board is faulty and instructs to change the board. All I can do is to check the electrolite condensators and the diodes on the main board. Do you have any ideas what to do if all the condensators and diodes are OK ?
At 5:27 you can see just to the right of where the power supply connects to the main board there's chip beside a black round inductor and some caps, that is a regulator and you will want to check there is some kind of normal voltage there like 3 or 5 (I don't know what it should be). Also the white flex and other wires that go to the front panel see if they printed on the PCB what each pin is and if there's a mention of voltage test to see that's present. If one is missing follow the traces back to the source and look for bad components or a short. If all voltages seem present and correct maybe it's brain dead. Check power button has a voltage on one pin that is pulled to ground when pressed, often this is sourced from the processor so if missing maybe processor has no power or hasn't booted. Using a scope check there's a clock signal on the main processor (big chip in middle, look for datasheet for pinout), also check reset pin isn't active for some reason. If clock and reset ok look for an eeprom chip and use scope on data lines to see if it's reading it at plug in and/or when you push power button. Many things you can test for to try figure out what part isn't working, hopefully that gives some direction!
Revisa los condensadores cerámicos siempre son esos
*_You sound like a fellow Kiwi... We should never underestimate the ability of a Kiwi, as isolated as we may be, to fix any problem, be it fixing a piece of broken farm machinery or splitting the ATOM*_.
Kiwi yes, not a truer word spoken!
Sir i have a sony cmt sbt20 my problem is system is good working but I have press equalizer button flat pop and other or mega bass button the bass down low bass and restart the system bass is generally works good
Please tell me what js problem
I really don' t know sorry.
I wish you lived in Florida lol. Got a few projects.
Did you ever find out any way to repair the display?
I think it is just intentionally dim, somebody commented their one is also very dim.
@@JonnyFix thanks. I think mine has actually failed
How to open front cd cover..
First, take out the rear metal plate. Just pop out the bottom metal clips with a flat screwdriver and you can slide it up. After that, you can find a big white plastic gear on the bottom of the CD player. Use your finger to turn it until the mechanism pushes out the CD tray. After that, you can take the silver front plastic cover from the tray, four clips are holding it. After that, you can use the same mechanism to close the tray. Now you can take the CD player out.
My cd won't eject. Might have to do this..
we have an earlier version of this - SONY CMT S20B - the display is so dim it's only readable in a dark room, cannot adjust brightness. Shame on SONY.
I also have one with a failed display
Trashy display, can't read it in daylight.