It was dead when I got up this morning, only the standby LED was lit, pressing the power button produces a brief illumination of the backlight and a faint thump in both speakers, on initial inspection I spotted a bulged electrolytic through the vent grille on the R/H side.
When I contacted Hitachi UK, they replied that this is regarded as a throwaway item and no service data is available.
Does anyone know of a schematic anywhere or any info on known stock faults?
TIA.
Chances are they didn't make it. You'll either have to identify the OEM, or replace the electrolytic and trouble shoot with what information you can find for identifiable sections.
-- Adrian C
The LCD was intermittent from new and the backlight was so dim it was often hard to tell.
At least now I have an excuse to open it up and have a look.
Most likely the unit was made by a subcontract assembler. They build these very cheaply, and thus it does not pay for them to support this type of product. Most consumer products are made this way.
You can take the unit apart and identify the capacitor that is bulged. Then you can order a generic replacement from an electronics parts supplier. You will probably find that there is a lot more at fault than just the capacitor. Something in the circuits may be at fault that caused the capacitor to overheat.
You will need the instrumentation, tools, and engineering information to be able to troubleshoot the unit. Then you will have the issue to find replacements for any specialized parts that were custom made for the manufacture. These are referred to as proprietary parts. This is very common practice with today's appliances and devices. I have seen everything from TV's through to appliances that are considered non serviceable throw-away products.
Jerry G.
_______________
and
s?
You can take the unit apart and identify the capacitor that is bulged. Then you can order a generic replacement from an electronics parts supplier. You will probably find that there is a lot more at fault than just the capacitor. Something in the circuits may be at fault that caused the capacitor to overheat.
You will need the instrumentation, tools, and engineering information to be able to troubleshoot the unit. Then you will have the issue to find replacements for any specialized parts that were custom made for the manufacture. These are referred to as proprietary parts. This is very common practice with today's appliances and devices. I have seen everything from TV's through to appliances that are considered non serviceable throw-away products.
Jerry G.
The bulged capacitor was guilty as charged (excuse the pun) the ESR was over
5 Ohms - I don't have a meter to measure capacitance as big as 2200uF. However that wasn't the whole story, when I cleaned off the solder one of the capacitor's solder pads dissapeared up the solder sucker - it was as if the pad had been die-cut around the edge of the solder mask, so I had to scrape the solder mask along the track and solder a link across the hole in the copper so I had something to solder the replacement capacitor to.The only 2200uF/16V I could find was fatter than the original and as it stands between the fins of a nearby transistor's heatsink, the fatter capacitor pushed the heatsink over a bit so it fouled a nearby 100nF disc-ceramic cap. The 100nF is in parallel with the electrolytic, so I removed it and put a couple of 150nF ceramic chip capacitors I nicked from a scrap HDD logic board onto the print side.
Looks like I caught the fan just in time! It was a bit stiff, so I peeled the label and squirted some GT85 PTFE freeing oil in the bearing to get it spinning again, then hooked it up to a spare 12V connector on the PC to work a few drops of Slick50 into the bearing while I was working on the rest of the unit.
One thing is a little strange - after the repair I had to turn the volume down 3 presses on the down button, so obviously some part of the audio path is supplied by that PSU section which I thought only did the front panel logic board. I'm surprised that there were no disturbances or hum on the audio as the capacitor went into it's death throes.
Hi!
I am not too surprised to hear this. It could well have been bad from day 1.
That would surely be the next thing. I envisioned this set as a portable, but it must be something a bit bigger than that since it has a cooling fan. There's no excuse other than cheapness as to why these fans fail.
(Seriously. I have computer fans that were made in 1987 and are still going strong.)
That seems like a pretty common outcome...the circuit works fine until one day the capacitor really gives it up. Somehow it struggles along, maybe due to reserves in the design? Sometimes other components fail when the capacitor stops working, but in this case, it sounds like the unit has been restored to perfect health.
William
It been going a few days now - so fingers crossed.
The cap I took out is marked "KSC", the top is bulged but the creases didn't split - it tried to vent by pushing the rubber plug out the other end.
The replacement came from stock I keep for repairing SMPSUs, so its high temp and ultra low ESR, I also upgraded the ceramic capacitor in parallel with it, its a 16V cap with less than 12V on it and doesn't seem to be particularly hard worked so I'm guessing it was a crap capacitor to start with.
Almost certainly, I have a fan the right size in stock but CBA grafting the long connecting lead to it, so I hooked the old one up to 12V supply to run some PTFE lube into the bearing while I worked on the PSU.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.