Hitach TRK-8130E recap

[sssboa]

Hi

So I recapped this $20 box. Some could say - a waste of time, others would say - an incredible waste of time.

For anyone curious, there was one bad cap, and it was the biggest one, 2200uF, measured 1300uF.

Take care, of your boxes of course,

Andy

 

[T-STER]

Nice little box and always good to save another one, well done.

 

[sssboa]

Nice little box and always good to save another one, well done.

Thx.

I have a feeling that it's better sounding than TRK-8080E or maybe it's the full recap that did the job. I wanted to fully recap 8080E but caps are very difficult to remove as the whole traces are covered with solder and components are not marked on the solder side as it is in 8130E. Maybe will try again with print of schematics and better desoldering gun. So far just replaced some of the smallest caps below 1uF with film caps and some of the biggest 1000uF and 470uF kind but the big ones tested like new.

In TRK-8130E something turned into black goo like liquid tar which soils everything, I didn't see it in 8080E.

In general do you think that big late 1970s Hitachis stand up well against smaller early 1980s?

 

[T-STER]

I think late 70s early 80s Hitachis are very well built and sound good. Never the bassiest boxes but good nonetheless.

 

[MyOhMy]

Good work, I have a couple of these as I really do like this model. This is the model I bought in 1981/2, I currently have two plus a donor box for spares.

 

[sssboa]

Good work, I have a couple of these as I really do like this model. This is the model I bought in 1981/2, I currently have two plus a donor box for spares.

So I have some questions

Do you have squeaking sound when you tune to stations with the tuner knob? I don't know what should be lubed for this.

I suppose you didn't have any problems with the white Fuji relay with 111C marking on it?
https://boomboxery.com/forum/index.php/topic/28184-relay/

Shame that line-in does not work really. Have you tried any line-in or bluetooth mod?

Where did you buy the belts for this model?

 

[MyOhMy]

Good work, I have a couple of these as I really do like this model. This is the model I bought in 1981/2, I currently have two plus a donor box for spares.

So I have some questions

Do you have squeaking sound when you tune to stations with the tuner knob? I don't know what should be lubed for this.

I suppose you didn't have any problems with the white Fuji relay with 111C marking on it?
https://boomboxery.com/forum/index.php/topic/28184-relay/

Shame that line-in does not work really. Have you tried any line-in or bluetooth mod?

Where did you buy the belts for this model?

I have no squeaking noise from the tuning operation, could the tuning cord not be fitted correctly (too tight?)?

Both my models work fine with no component issues other than the temperamental clocks.

I have not tried any Line In/DIN/Aux/Bluetooth facilities.

 

[sssboa]

@%&! Sorry for cussing
I just broke the aerial on this box at the very base. I was trying to unbend it and it snapped. Turned out to be very fragile. I've fitted an aerial from TRK-8080. I am not sure if it works as good. It's shorter and thicker. Strangely I have to position it very differently to the original to get best signal.

I loosened the tuning cord a bit by changing its route slightly and the squeaking is almost gone.

BTW. There's a socket at the back for an external FM antenna. I have never seen an aerial with a plug like this. Can anyone give me a link to such an aerial?

I just fitted the new relay in. All works alright.

 

[MyOhMy]

With regard to the rear aerial connection, this is quite a common connection on BB's, Music Centres etc. of the era. I bought a couple off eBay(UK) at quite a low cost, I hope ths pic below will help

 

[sssboa]

With regard to the rear aerial connection, this is quite a common connection on BB's, Music Centres etc. of the era. I bought a couple off eBay(UK) at quite a low cost, I hope ths pic below will help

DSCF3741sfw.jpg

IEC 3-pin male plug (DIN 45316)
Not available in the UK ATM. Does it improve reception over the telescopic one?

 

[MyOhMy]

With regard to the rear aerial connection, this is quite a common connection on BB's, Music Centres etc. of the era. I bought a couple off eBay(UK) at quite a low cost, I hope ths pic below will help

DSCF3741sfw.jpg

IEC 3-pin male plug (DIN 45316)
Not available in the UK ATM. Does it improve reception over the telescopic one?

I've never actually compared the reception qualities as I have used these antennas.aerials with Music Centres where no other convenient aerial arrangement would fit due to shelving above the Music Centre. The flexibility of these aerials are their biggest asset.

Looking at the simple design of the connectors, I would suggest you may be able to insert a twisted speaker wire secured with a toothpick/cocktail stick into each of the female parts as a temporary fix to see if it's worth investing in an aerial first. I suppose you could even do this with the rear casing removed.

 

[floyd]

@%&! Sorry for cussing
I just broke the aerial on this box at the very base. I was trying to unbend it and it snapped. Turned out to be very fragile. I've fitted an aerial from TRK-8080. I am not sure if it works as good. It's shorter and thicker. Strangely I have to position it very differently to the original to get best signal.

I loosened the tuning cord a bit by changing its route slightly and the squeaking is almost gone.

BTW. There's a socket at the back for an external FM antenna. I have never seen an aerial with a plug like this. Can anyone give me a link to such an aerial?

I just fitted the new relay in. All works alright.
hitachirecapped.jpg

I know it was the relay and you know how because if there's one there it will f*** you eventually. I repaired enough old School Kenwood car amps to know all about these relays.

 

[sssboa]

With regard to the rear aerial connection, this is quite a common connection on BB's, Music Centres etc. of the era. I bought a couple off eBay(UK) at quite a low cost, I hope ths pic below will help

DSCF3741sfw.jpg

IEC 3-pin male plug (DIN 45316)
Not available in the UK ATM. Does it improve reception over the telescopic one?

I've never actually compared the reception qualities as I have used these antennas.aerials with Music Centres where no other convenient aerial arrangement would fit due to shelving above the Music Centre. The flexibility of these aerials are their biggest asset.

Looking at the simple design of the connectors, I would suggest you may be able to insert a twisted speaker wire secured with a toothpick/cocktail stick into each of the female parts as a temporary fix to see if it's worth investing in an aerial first. I suppose you could even do this with the rear casing removed.



Have you tried to set bias current for the amplifier? I see there 2 trimmers - RT461L and RT461R, one for either channel and the schematics show to 2 resistors R400L and R400R with arrows coming from the trimmers but they don't mention about the target current we should read there.

Also I wonder what the metal box under the trimmers is. It is marked L461 OSC BLOK.

Oh, I just noticed it's under the tape recorder adjustment, it should be 4mV across either of these resistors by adjusting the trimmers herein mentioned. I am not going to use the tape player, just the radio, so I suppose I don't have to care about these settings?

 

[MyOhMy]

Have you tried to set bias current for the amplifier? I see there 2 trimmers - RT461L and RT461R, one for either channel and the schematics show to 2 resistors R400L and R400R with arrows coming from the trimmers but they don't mention about the target current we should read there.





Also I wonder what the metal box under the trimmers is. It is marked L461 OSC BLOK.

Oh, I just noticed it's under the tape recorder adjustment, it should be 4mV across either of these resistors by adjusting the trimmers herein mentioned. I am not going to use the tape player, just the radio, so I suppose I don't have to care about these settings?

I've not been involved with any of the components you mention, I'm afraid my technical skills don't go that far.

 

[sssboa]

Have you tried to set bias current for the amplifier? I see there 2 trimmers - RT461L and RT461R, one for either channel and the schematics show to 2 resistors R400L and R400R with arrows coming from the trimmers but they don't mention about the target current we should read there.





Also I wonder what the metal box under the trimmers is. It is marked L461 OSC BLOK.

Oh, I just noticed it's under the tape recorder adjustment, it should be 4mV across either of these resistors by adjusting the trimmers herein mentioned. I am not going to use the tape player, just the radio, so I suppose I don't have to care about these settings?

I've not been involved with any of the components you mention, I'm afraid my technical skills don't go that far.

You don't need technical knowledge. Only a flat screwdriver, multimeter and schematics.
There's an instruction with drawings in the service manual.

Trimmers are variable resistors or potentiometers, they have a slit on top to be turned with a flat screwdriver. There are plenty of trimmers on the board, most for adjusting radio tuners, we are interested in the two I mentioned above. You connect probes of your multimeter to both sides of a resistor I mentioned and you turn the corresponding trimmer with screwdriver until the multimeter shows 4mV. You do it with the resistor and trimmer with symbol L (left channel), then the same with trimmer and resistor with letter R (right channel). I understand it's adjusting recording current for the tape head. They advise it as the last stage of the head maintenance. Before that there's playback adjustment with Azimuth screw wherever and whatever that screw is and measuring at DIN OUT for highest current.

I am new to boomboxes, I suppose that most of them are adjusted in a similar way so someone could clarify. Personally I am interested if there is any adjustment process for setting bias and idle currents for amplifier as at is in separates which are less for casual listening than a boombox though.