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** Hitachi TRK-7620 (3D7) - no more fixed AC lead **


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#1 jimmyjimmy19702010

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Posted 01 April 2017 - 12:27 AM

Hi Guys,

A while ago I posted a thread about a cheapie 3D7 I scored. Since the restoration, this box has seen some very heavy use as it's just such a great box. The only 'issue' I have with this particular model is the penny pinching fixed AC lead you have to contend with. Continually rolling it up and pulling it out after each outdoor use is a real pain so it was time to do an upgrade.

First thing to do was to find a suitable location for the new AC cable input. I didn't want to have a messed up rear panel so a connector that sat inside the battery compartment seemed like the way to go:
Attached File  IMG_3598.JPG   97.08K   1 downloads

It does mean you have to remove the battery cover to plug and unplug the cable but that's much more convenient than rolling up that stupid fixed cable. :-)

Ok, now what sort of input should we use? The answer was the input from a parts Sanyo M9998. I noticed the Hitachi TRK-9150 uses an identical AC input.
Attached File  IMG_3611.JPG   81.92K   1 downloads

Next I had to desolder the connector from the circuit board it's attached to. As the Hitachi has a separate AC/DC switch, I won't need to use the battery defeat switch on the connector.
I also won't need to use the 12V input as the Hitachi already has one.

Now it was time to cut a hole for the connector to pass through.Attached File  IMG_3599.JPG   85.1K   1 downloads

Just had to visit the hardware store for some fine thread nuts and bolts of the right size. I didn't want to risk using self tappers for this job.

Attached File  IMG_3612.JPG   109.04K   1 downloads
Attached File  IMG_3601.JPG   70.57K   1 downloadsOk now with the plug installed and a little super glue on the threads, it was time to cut the old cable and solder it to the new AC input.
] Attached File  IMG_3602.JPG   86.35K   1 downloadsAttached File  IMG_3603.JPG   91.87K   1 downloads

With the plastic cover fitted:Attached File  IMG_3604.JPG   85.72K   1 downloads

Next I had to thoroughly clean out all the plastic shavings that tend to get everywhere inside the box.

All finished and operational:
Attached File  IMG_3608.JPG   103.67K   1 downloadsAttached File  IMG_3607.JPG   117.78K   1 downloads
Attached File  IMG_3606.JPG   80.83K   1 downloads
As the power cord still passes through the corner of the battery cover, from the outside, the Hitachi still looks factory. :-)

I know it's not a big deal but if you've spent anytime cranking a 3D7, 3D8 etc, you'll understand why I bothered to do this hack. :-)
Old power cord be gone!!! :lol:Attached File  IMG_3610.JPG   114.5K   1 downloads

Thanks guys,

James.... :-)

#2 baddboybill

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Posted 01 April 2017 - 07:25 AM

Very cool Jimmy!!!

#3 Reli

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Posted 01 April 2017 - 09:33 AM

NIce, good idea!

 

I have to say, I have a 3D80H, and I'm not impressed by the bass at all. Is that model the weakest of the 3D's?

 

Also the Surround doesn't seem very natural, and it cuts bass......So I leave it off.



#4 Northerner

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Posted 01 April 2017 - 11:56 AM

Nice idea :-)

#5 jimmyjimmy19702010

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Posted 01 April 2017 - 02:37 PM

NIce, good idea!

I have to say, I have a 3D80H, and I'm not impressed by the bass at all. Is that model the weakest of the 3D's?

Also the Surround doesn't seem very natural, and it cuts bass......So I leave it off.

Thanks guys. The 3D80 is the best looking 3D box according to some. After working on many of the big 3Ds, I'd have to say the 3D8 has the strongest bass followed closely by the 3D7.

The secret to the low end performance of the 3D7 & 3D8 is the power that centre speaker receives. Instead of 2 16cm speakers sharing 8 watts RMS (3D80), the long throw centre speaker in the 3D7, 3D8 receives 8 watts RMS on its own which allows that single speaker stronger output..Attached File  IMG_3614.JPG   92.84K   1 downloads

#6 Reli

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Posted 01 April 2017 - 04:26 PM

Makes sense. Yeah, those dual subs on the 3D80 look good & that's the main reason I bought it, lol



#7 jimmyjimmy19702010

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Posted 01 April 2017 - 11:38 PM

Makes sense. Yeah, those dual subs on the 3D80 look good & that's the main reason I bought it, lol


If you want more power in a Hitachi 3D, grab yourself a 3D70. It's the only 3D model that takes 10 D cells (15v).Attached File  IMG_3617.PNG   481.98K   0 downloads