Hitachi AX-M82D CD/DAB/FM/Cassette.

[ian field]

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.

 

[Adrian C]

On 02/03/2010 17:06, ian field wrote:

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.

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

 

[ian field]

"Adrian C" <email@here.invalid> wrote in message
news:7v50g9Fr1oU1@mid.individual.net...

On 02/03/2010 17:06, ian field wrote:
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.

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.

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.

 

[Jerry G.]

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.

_______________


On Mar 2, 12:06 pm, "ian field" <gangprobing.al...@ntlworld.com>
wrote:

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.

 

[ian field]

"Jerry G." <jerryg50@hotmail.com> wrote in message
news:a6be7d46-3863-476c-84a4-b3da6b58351a@f35g2000yqd.googlegroups.com...
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.

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.

 

[William R. Walsh]

Hi!

The bulged capacitor was guilty as charged (excuse the pun) the ESR was
over 5 Ohms

I am not too surprised to hear this. It could well have been bad from day 1.

Looks like I caught the fan just in time!

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.)

I'm surprised that there were no disturbances or hum on the
audio as the capacitor went into it's death throes.

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

 

[ian field]

"William R. Walsh" <newsgroups1@idontwantjunqueemail.walshcomptech.com>
wrote in message news:wqedne8MFYHFAwzWnZ2dnUVZ_vCdnZ2d@mchsi.com...

Hi!

The bulged capacitor was guilty as charged (excuse the pun) the ESR was
over 5 Ohms

I am not too surprised to hear this. It could well have been bad from day
1.

Looks like I caught the fan just in time!

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.)

I'm surprised that there were no disturbances or hum on the
audio as the capacitor went into it's death throes.

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.