hi all, i need a little help i bought a hitachi W500 super woofer its the ultra rare one with cd player its cosmeticaly mint and even came with the remote control but thats where it ends.

The cd player was dead (not even display) and the tapes were dead and the digital tuner worked on fm only the speakers are mint but the sound isnt it hums and the woofers sound terrible when switched on, supprisingly the electric volume knob (yep thats right the volume control is servo assisted when you turn it the moter starts to drive the knob and it goes on its own by remote) all works and no control is scratchey.

for the interest of others i will tell the story of repair, first i thought the speakers should be the first thing to be fixed so i set up a work bench with my scope on the preamp set to a radio station, the wave form i picked up for this was good and indicated pre amp ok, so i moved to the amp chips L+R looked good but when you press the 3d button the wave got smaller so i moved to the other amp chip and it was full of spikes, noise and it was getting very hot, so i managed to get new la chip of the internet from china and 2 weeks later it arrived and so i fitted it and presto the wave looked great and sound was great job done.

now for the radio bands, his was obvious when i took the top cover off, the ferrit rod had the coil sliding about the wax had come loose so i tuned in to the same station as another digital tuner i have and moved the coil untill the station was tuned perfect then glued in place sorted all 4 bands work.

now for the tape decks belt drive 1 motor, no life when button pressed but audible click so know amp works, the belts were intact and had minimal wear on them decks look like new so tested the motor for resistance confirmed so then a looked at the motor run switches 2 in parallel 1 for each deck they were ok so tested for live at the switches nothing, so traced wires back to power board where i found a rather burned resister on next to the speed pot it was 10k so i have plenty of them replaced it decks fired up but sound on both was muffled, cleaned and realined the heads and sound great but slow so linked deck switch to spare test deck and 2 tapes with beat created same on pc and set the pot so the beats stay in phase perfect tape deck complete.

now for the cd player now i knew this would push my skills to the limit, so first thing i tested was the function switch output 11.6v so thats ok followed track out to ribbon which goes to cd main board 4.8v here (resistors in path) followed track to power transistor npn type 3.0v was the switch to enpower cd board so tested supply leg on transistor 5.0v present from power board near transformer but nothing from the output leg of transister so bridged transister with probe lead and the lcd screen came on (result) so trip to maplins and new transistor fitted, so i now have power but still the cd will not load, i hear clicks on the pick up but nothing spins also speaker hum, so scope on power board large cap sticky (had been leaking) 2000uf so replaced cap hum now gone and no spikes in wave anymore.

still no cd, tested spindle motor had resistance and spun when powered then tested tracking motor also ok and when safety catch bypassed the lense can be seen moving trying to focus, this can only mean 1 thing so using my mobile phone camera to detect the infra red laser (due to red eye tech mobile cameras will show infra red light as red on display) i now confirm the laser is dead (prob blew the transistor mentioned prior) so blank drawn gave up for few months and then bored one day took the laser pickup out and noticed a part number so googled it and guess what available brand new (still used in new blasters) for £30 including post so withdrew to contenplate then card in hand ordered new laser.

arrived 2 days later, exited i fitted it and wow it works cd spins and tracks play but very sensitive to skipping, so scope on rf channel 1 and ch2 on test point i could see the readings show the focus was wrong and the tracking so using the 6 pots to adjust the various aspects it now works perfectly took very long time to get it right even with scope.

sorry for the length but i wanted to say it goes to show even the most doubtfull of boxes will work.

the bit i need help with is a button on the cd player labeled T.P. (push on push off) makes contact and switches voltage but i cant see any effect so hopefully some one knows what it for so i can fix it.

heres some pics.

Well done! You really deserve this one considering all of the work you've put into it. Isn't fixing it yourself a great thing? Its sort of like looking at a giant puzzle and needing to solve it without any hints.

My hats off to you! Beautiful box and great detective work!

Wow that was very labor intensive. I wish I had skills like that.
Makes you wonder what happened to the radio to cause all those problems. Especially with the blown components,like a voltage spike from lightning or something.

well the laser probably wore out and blew the transister when it went, the amp chip had an internal short which can happen in normal use the capacitor was age related and i think the ferite antena was damaged in transit, it was boxed really well but you know what couriers can be like even if a drop doesnt break the case still the components within have experienced a large shock.

thanks for the comments im really pleased with the hitachi cranking a cd now actually.
hopefully isolator will know what the button does he must have one of these

also for isolater i noticed this super woofer doesnt have the usual rubber edged woofers these ones are paper edged similar to the fullrange they seem to have a much tighter bass and dont distort at full volume they are larger in size than the fullrange wheras the other 4 spkr 3ds are the same size.

you need some sort of award for services to Hitachi 3Ds for that fix upjob, very well done!

sounds like that one you had was a "Friday afternoon" model, but you've put that right for sure.
As for that switch... if it's the small push-button switch next to the CD buttons, the one on my 2 CX-W500s is labelled "M.B.". You can see it in this (big) pic from x9moto:

If memory serves it was a Beat Cut type switch, & I never found out why it was positioned with the CD buttons...

Your Hitachi boombox looks quite nice and I always like to see stories about boombox repairs.

ah thanks very much for the comments that puts my mind at rest the switch probably is ok then because i havent tried recording, also how is your cx w500 when playing cds does it skip at very high volume when the bass is turned up because on hi-tech music ie high bpm it does and it tends to be a long range skip ie from middle of track back to begining of track but softer music doesnt seem effected this is present on battery and mains, i checked power supply voltage on cd main board and it is the same as the markings on the board indicate.

my current suspect is the rubber suspension on the cd sled it seems a little hard think the rubber might have aged but since i doubt i can by any for sensible money i may have to live with it

quote:

Originally posted by x9moto:
...how is your cx w500 when playing cds does it skip at very high volume when the bass is turned up...

that's funny. To be fair to your CX-W500, I don't own one 1pc CD boombox that doesn't skip if you crank it hard enough - all those vibrations are bound to do it. As you say, the CD transport suspension might be getting a bit old, but there's alot of speakers just below it creating a lot of vibes!

As for the long skip issue, I haven't noticed that on mine, but you've had to tweak stuff to get it to work at all. This may have had an effect on something in there.
You've done plenty more than I could manage already... hats off to you mate

yeah ok thanks i am glad to see it thumping again even if only at 3quarter volume but hey it was cheep enough cant really expect every thing with a 20 yr old box its done well, i do have 1 piece though that can seem not to skip no matter how hard you crank it and thats the kaboom bring the thunder!!

If all else fails then just use your favourite source through the line in?

(Perhaps use that line in to feed a portable CD player into it?)

quote:

Originally posted by x9moto:
...i do have 1 piece though that can seem not to skip no matter how hard you crank it and thats the kaboom bring the thunder!!

good point, I have an RV-NB10 & you're right - The CD is solid at any volume, even when playing MP3 discs. Could be because the woofers are in a tuned enclosure rather than just bunged in the cabinet...

Thats is a real talent you got,i wish you would get a few grail boxes like a GF777 with lots of faults,do a full and detailed repair,using your scope,so to help a few novices out on there faulty 777`s..you`de be doing a great service and help alot of peeps out..

tell you what ghettoman i would absolutely love to have even 2 of the boxes you guys have but i just dont have the money even broken ones cost a fortune when you are talking top end.

i would like gf777, discolite, lasonic, bombeat, one of the huge crowns, and many more.

really dont know how good i would be with the real monsters you see the newer they get the easier they are to fix and i kind of have a guy from work to thank for doing what i can because he is a semi retired electronics engineer and gave me his old lab scope (handheld) and i could never say how gratefull i am for that because i could never afford to buy one its a dual chanel 50mhz with memory and multiplier functions still new in box.

hopefully something cheap will appear so i can have a go but i think as long as i had a circuit schematic i should be able to fix them
but i would not want to touch anyone elses untill i was confident on my own because i know that many of your boxes are your pride and joy and i would hate to be responsible for making the problem(s) worse.