Hitach TRK-3D30E Help!
 

HI All,

I would like to have a go at restoring My Hitachi TRK-3D30E Cassette Boom Box (Is this in the right section?) the obvious faults I can see are.

1. The Aerial needs replacing.
2. The drive belts have turned to rubbery mush.
3. Deck one emits a high pitch wine/screeching sound through the speakers.

The Aerial is the least of my worries, but if anyone knows of a good source that would be great, how do I find the belt sizes for the 4 belts? I have looked in the service manual but it doesn't give any sizes and the old belts are not there they are just rubbery sticky bits of goo, they are also hard to reach to clean. I see there are some belts kits available from Germany but the price is quite high including postage, is there a UK source for them?

How do I start to diagnose the high pitched squeal, what's the most likely cause? I have a multi meter and can solder quite well so replacing parts is not a problem.

Regards,
Chris.

Re: Hitach TRK-3D30E Help!
 

Try cleaning the sliding record play/record switch before investigating the squealing in depth.

Insert a blank cassette, go from record+play to stop a dozen or so times, and see if it's any better. If not, squirt some Servisol Super 10 switch cleaner into the actual switch on the PCB (follow the linkages from the buttons), taking care it doesn't get onto the decks themselves, and repeat.

Good luck,

Nick.

Re: Hitach TRK-3D30E Help!
 

I found some screws that I was not aware of, they were covered in gunk, once out I got good access to everything, I'm not sure what the Squealing sound was but once I opened everything up it stopped. That is the end of the good news though, once Dismantled for cleaning, it looks like some caps may have leaked and there is some quite bad PCB damage, looks like I've got some work on my hands repairing this one :-)

Re: Hitach TRK-3D30E Help!
 

Once I clean the PCB up is it ok to squirt those sliding pots with switch cleaner I've never seen this type before or is there any suitable lubricant for them?

Does anyone know what the belt sizes are for this model Hitachi TRK 3D30E, if not at least what the width is or are they square etc?

Re: Hitach TRK-3D30E Help!
 

Hi!

I've just bought a 3D50E that appeals condition-wise & price-wise to me and appears very similar externally, so I'll let you have belt details & any other help you need when it arrives!

Chris Williams

Re: Hitach TRK-3D30E Help!
 

Thanks Chris, That would be great :-)

I have cleaned the PCB up a bit, I tried IPA but it just turned into a sticky mess, I'm guessing it just reacted with the old flux, so I had to use fairy liquid and water with a toothbrush, (I know it really should have been de ionized/distilled water, but I didn't have any to hand), it cleaned up nicely and then I sanded the black damaged traces with a nail file and laid some solder over the cleaned traces to protect it a bit, one of the traces was so thin it lifted, so I had to use a jumper wire, I haven't finished the PCB yet there are a few small traces left to do, then I'll re cap it before going any further :-)

Re: Hitach TRK-3D30E Help!
 

For the belts, you can simply tie some string or dental floss around the pulleys, remove, and then measure the diameter to get a rough approximation. Universal belt kits are available, and often don't cost as much as dedicated belt kits, but you always run the risk of a missing size.

Best to stick to a reputable source as often very cheap kits from China are sometimes made up of substandard rubber, possibly offcuts from other things. They can be misshapen and uneven across their length which will invariably lead to all sorts of wow/ flutter issues.

Re: Hitach TRK-3D30E Help!
 

Thanks John,

Do you have any links to reputable sources for the belts? I usually use ebay for everything but try to stay away from Chinese sellers where possible.

Re: Hitach TRK-3D30E Help!
 

I was looking at the service manual and it says C516 should be 47uf 10 v but on my board C156 is a 4.7uf 50 v what is more likely someone putting the wrong part in on the production line or the parts list being wrong even a previous repairer being wrong? It also says in the manual that C514 L & R should be present but they are not on my circuit board not even printed where they should be, I wanted to replace all the electrolytic capacitors but unsure what to do in this case, normally I don't think I'd replace all of the capacitors, but as there was a lot of damage on this board, I think it's best to replace them.

Re: Hitach TRK-3D30E Help!
 

It's been ages since I last bought any belts, although UK based sellers via eBay are probably your best bet. You tend to run into less problems with the small (square sectional) type belts than with the larger flat belts (as used in Hi-Fi tape decks etc), so you should be OK.

With regards to the caps, you're probably better off replacing like-for-like. It's possible the design has gone through a number of revisions, so your service documentation might not always be a 100% accurate representation of what is in front of you. They often add a little a disclaimer such as 'design and specifications are subject to change at any time'.

Re: Hitach TRK-3D30E Help!
 

Hi Guys, Does anyone have a Different Service manual or Amended Manual other than the March 1989 version for the TRK-3D30E? or any experts on here know what would suit capacitor 516 better, I'm in the process of re capping the board and C516 has a 4.7uf 50v on board but my service manual matches the online PDF which says it should be a 47uf 10v cap? I know a few have said just replace like for like, but this particular stereo sounded really bad to begin with so may have had a previous repair or two, I'm only an amateur with electronics so I have no clue what would fit here better.

Thanks,
Chris.

Re: Hitach TRK-3D30E Help!
 

Hi Chris,

I have the March-89 servicemanual only and it shows the cap. to be 47uF as you say.
I believe there is good reason for it to be 47uf as it's the coupling capacitor for the inverting amplifier-section of the push-pull amplifier for the sub-woofer.
You want the low-frequency cut-off to be low for the inverting amp., so it will follow the non-inverting amp. as close as possible and that indicates 47uF, not 4,7uF.
Take a look at the input signal-path for the signal. From the summing junction of R511/R512 the mono-signal passes through the low-pass filter R512~R514/C511, 512, 517 stripped of anything but the lowest frequencies.

In any case, this sub-woofer amplifier is only active when the 3D switch S501 os on, so it has no influence on the general sound of the stereo-amplifier.

Unfortunately Hitachi choose the reverse the inverting and the non-inverting amplifier sections of the IC compaired with the original Sanyo data-sheet for LA4558. You should have a look anyway.

Rgds,

/Torben

Re: Hitach TRK-3D30E Help!
 

Thanks Torben,

I am only a beginner when it comes to electronics, but I trust your judgement :-) I will go with the 47uf much appreciated.

Chris.

Re: Hitach TRK-3D30E Help!
 

I went with the 47uf as Torben suggested and the manual and I am happy to report that is sounds really good now after a full re cap new belts etc all that’s left to do now is give it a good cleaning and protect the exposed traces, but thanks for your help it’s working nicely :-)

Re: Hitach TRK-3D30E Help!
 

Can I just warn you about those slider controls? They have a tendency to fall apart if switch cleaner is used on them - I speak from experience, though back in the day I was able to just get new oness from Hitachi. Maybe using a little silicone grease so they move smoothly will help.
These could sound really good - ages sincve I've seen one though!

Re: Hitach TRK-3D30E Help!
 

:thumbsup:

/Torben