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My humble Hitachi 9140E is finally delivering the goods!!


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#1 jimmyjimmy19702010

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Posted 01 September 2012 - 12:42 AM

Hi Guys,

Well to make a short story long, soon after I started here at Boomboxery.com, I posted about a Hitachi TRK-9140E I purchased from Ebay. Yes, fully operational etc, etc, etc! It arrived well packed but it had a very low left channel, completely dead tape deck, poor sound quality and needed a bath.

The first port of call was a clean. I separated the internal chassis from the case and gave the casing a warm bath. Next job was to clean/lube the band selector switch (the cause of the low left channel). Next I cleaned the scratchy pots and function selector. Now at this stage it sounded ok on radio mode but the left channel output kept dropping down on its' own every couple of minutes. If you rotated the band selector a few times it would come good but only momentarily.

At that stage, a service of the deck was beyond me so I visited my local repairer and had him service the deck with new belts etc. So now the deck worked fine if a bit muffled but the left channel issue was still there. Also, the sound quality from 3/10 volume and up was terrible - distorted and flat with very little treble. The tech tested the amp output and said" it was to spec and maybe this is how crappy these old radios sounded!" :thumbsdown: I knew nobody would have bought one of these things back in the day if it sounded like this one did! I must admit I was a little disappointed as it sounded like it may have needed a recap. I certainly couldn't afford to have a tech do that job so I reluctantly shelved the 9140E and moved on to other radios.

Every now and then though, I'd pull the old girl out and see if by some miracle it had sorted it self out - no luck apart from the low left channel issue had corrected itself.

Fast forward to this week, I spot a TRK-9200 on Ebay. The wording of the ad didn't include the words 'boombox or ghettoblaster' and didn't seem to be getting much attention - well the auction ended with only two bids. I scored this cheap but very rough Hitachi for $11.50 :thumbsup:

The seller was only 10kms away so the next day I go and pick it up - at 7.00pm in the guys front yard!

I get it home and fire it up - guess what? The left channel output is low! :-/ Unfortunately no amount of cleaning of the band selector sorted the problem. The unit cosmetically was a mess with cracked rear speaker casings, serial number etchings on almost all exterior panels too! The tape deck was dead and all the chrome was pitted or peeling off due to him having the unit next to the beach for 30 years! :thumbsdown: I thought I could maybe swap the nicer chrome knobs from the 9200W to my 9140 but again no dice. See the 9200 is defeatured and doesn't have a phono input, sleep function, exterior FM antenna connections, manual recording modes and levels, AFC of RIF controls. Anybody with a 9140E would know that if you turn the power switch off whilst a tape is playing, the unit continues to run only turning off at the end of the tape. The 9200W never had this feature for some reason.

Now I'm thinking I've just spent $11.50 for a new, very heavy paperweight! I got out my trusty 9140E and put them side by side for a visional comparision and get the idea to try the speaker boxes from the 9200W on the 9140E.

Yahoooo!!!!!!!!!!!!!!!!!!!!!!!!!! Suddenly my 9140E has become a bass and treble monster!!! People always talked about the 9140E as a beast but until now I didn't believe them. My original drivers in the 9140E also didn't look like any other 9140. Obviously, I decided to swap over the drivers and tweeters from the 9200 to the 9140E. I must admit, it was one of the most enjoyable half hours of boombox exploration knowing at the end of the process, I was going to have a fully operational and awesome sounding 9140!! :thumbsup:

After removing the old 9140 speakers, I realise they were not the original speakers. They were the right size with a similar magnet size but otherwise looked completely different. The cones were very, very stiff and gritty too. :no: The 9200W speakers were the exact same size but the cones moved freely and looked much healthier. So after I swap them over, I fire up the 9140W and I'm in heaven!! :drool: :drool: After months of wondering, my head unit wasn't at fault at all.

I then pulled down the head unit again to clean the recording bars due to a new fault where left channel is lost completely when you hit record. After giving them a good work over, I take a look at the tape head and realise someone had wound out the left adjusting screw leaving the tape head completely out of alignment!! :thumbsdown:

I re-adjust it back to the factory mark and give it a test - now I've got a beautiful, bassy sound with clear highs and record now works again!! :thumbsup:
The TRK-9140E now holds its own against the TRK-9300W with the 9140E pushing stronger bass. :breakdance:

These old late seventies/early eights TRKs are so over built it's almost funny - each detachable speaker box weighs 2.30 kgs on it's own!

Below are a few photos showing the huge driver magnets and the thickness of the speaker casings.

Photo of the 9140E after the speaker swap: now that's better!
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I've seen smaller magnets on 8 inch speakers!
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Non original, faulty and ugly old drivers & a tweeter missing its' dust cap: Be gone!!
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Super thick plastic casing:
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Defeatured dash board of the TRK-9200W:
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I know she's no beauty but she has got it where it counts!!

Sorry about the huge post but I'm so happy I had to share!! :thumbsup:

James... :-)

#2 baddboybill

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Posted 01 September 2012 - 01:16 AM

Great job James :thumbsup: it's always great to get these boomers back to great working condition :-)


Bad Boy Bill

#3 jimmyjimmy19702010

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Posted 01 September 2012 - 01:24 AM

Great job James :thumbsup: it's always great to get these boomers back to great working condition :-)


Bad Boy Bill

Thanks Bill.

I've got the 9140 beside me right now vibrating the concrete floor!! :thumbsup: It's only the info and advice from yourself and other Boomboxery members that gave me the confidence to pull down, repair and get this old girl working again - thanks!!

James... :-)

#4 Northerner

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Posted 01 September 2012 - 02:21 AM

I love hearing the story behind these things!...congrats on getting it boomin in the end! :-D

#5 jimmyjimmy19702010

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Posted 01 September 2012 - 04:11 AM

I love hearing the story behind these things!...congrats on getting it boomin in the end! :-D

Thanks. This Hitachi has definately been saved from ending up in landfill!

James.... :-)

#6 stormsven

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Posted 01 September 2012 - 06:28 AM

Super job dude. I love this Hitachi too :thumbsup:

#7 retrohead

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Posted 29 June 2015 - 04:52 AM

much love here.fantastic job :cool:



#8 riker1068

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Posted 29 June 2015 - 01:54 PM

Nice

 

 



#9 Reli

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Posted 09 January 2017 - 04:05 PM

Jimmy, do you have pics of the 9200 speakers you put into your 9140?

 

I own a 9140, and its speakers are Foster 3.2 ohm woofers and Foster 8 ohm tweeters.

 

I know they're original because I was the first person to crack these screws.

 

The sound quality sucks --- no bass   :thumbsdown:

 

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#10 jimmyjimmy19702010

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Posted 10 January 2017 - 12:25 AM

Hi Reli,

All of the 9140, 9150, 9200 drivers I've seen have looked identical: 3.2 ohm: Made in Japan.
Your drivers and tweeters look different. All of the 'Japanese made' drivers I've seen have a paper surround and tend to last.




From memory, the cap for the tweeter should be attached to the driver - I'd check to make sure the tweeter has a cap in circuit somewhere. Also, I've never seen that new looking foam in any Hitachi box. The Hitachi padding I've seen is a felt material. The piece of foam beside the tweeter looks like it might be blocking the bass port. Remove that piece and try it again.

For a giggle a while back, I tried blocking the bass port on my 9150W for a test - the result was zero bass!
If your amps are healthy, the bass and treble performance should be very strong. I'm talking big 1 piece beating bass.

I dunno, maybe Hitchi in the late 70s used brand name Taiwanese drivers and tweeters for a production run?!

#11 Reli

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Posted 10 January 2017 - 06:36 AM

There are blue caps, you can see them in this pic.  Honestly the sound is mostly mids and mid-bass.   Nothing deep, nothing very high.  Also, this one was sold in Germany and it doesn't have a separate Loudness switch (the Loudness is supposedly integrated into the Volume circuit), so maybe that's part of the reason.

 

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#12 jimmyjimmy19702010

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Posted 10 January 2017 - 06:42 AM

What do the drivers look like from the front? I bet that foam was blocking the port. The felt padding normally only surrounds the driver. No padding extends up the tweeter / port end of the speaker box.

I've also never seen that green goop used on the speaker screws before.
Why would a manufacturer make a bass port and then deliberately block it with foam?

I've never seen a 9140 with no loudness switch?

#13 BoomboxLover48

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Posted 10 January 2017 - 07:22 AM

This is a good break from those Sanyo M nightmares! :w00t:

Great job! Finally you brought it all back to life! :yes:

Happy for you!



#14 caution

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Posted 10 January 2017 - 12:02 PM

Took the 9150W apart last night to start its resto, boy, what a ratsnest of wires! Everything is pluggable until it comes to the deck. Boo!



#15 hardmen

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Posted 10 January 2017 - 05:41 PM

I snag the 9150 last week and this thing POUNDS...
what a nice sound box...

Nice work of restoration Jimmy.

Cheers.

#16 Reli

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Posted 12 January 2017 - 03:49 PM



What do the drivers look like from the front? I bet that foam was blocking the port.

 

 

Like this.  The surrounds appear to be resin-reinforced cloth.  I trimmed some of the foam insulation, and the sound seems to have opened up a little bit.......but this is no bass monster by any means.  It doesn't go deep at all, and it needs to be cranked to produce anything I'd call bass.  In other words it's the opposite of a Telefunken Studio 1. 

 

 

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#17 jimmyjimmy19702010

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Posted 12 January 2017 - 09:26 PM

Wow, they really do look like the original drivers from the front! You may just have an example that's got a worn amp or some other issue. Out of my 9200, 9140 and 9150, my oldest unit (9150) has by far the best performance.

I thought my 9140E was a good performing unit but the 9150 is far superior when compared side by side.

I know they all have the same amps so it's just pot luck.

#18 Reli

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Posted 12 January 2017 - 09:45 PM

Whats different about your 9150?

 

Speakers?  Anything?



#19 JVC Floyd

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Posted 12 January 2017 - 10:03 PM

There are blue caps, you can see them in this pic. Honestly the sound is mostly mids and mid-bass. Nothing deep, nothing very high. Also, this one was sold in Germany and it doesn't have a separate Loudness switch (the Loudness is supposedly integrated into the Volume circuit), so maybe that's part of the reason.

WP_20170109_13_29_27_Pro.jpg


I would at least remove the foam that's obstructing the bass ports . On a ported box if the vents are blocked even the slightest bit it will have a tremendous effect on the sound.if anything I would remove it all together and replace it with a small amount of poly fill.

#20 jimmyjimmy19702010

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Posted 12 January 2017 - 10:11 PM

Whats different about your 9150?

Speakers? Anything?

Nothing, all stock standard. Just has a much more powerful sounding amp that refuses to distort before getting very loud. It really thumps with the bass knob set to flat or at the 1:00 o'clock position. I usually have treble set at the 2:00 o'clock position for nice, crisp highs.

My 9240E in comparison, sounds flat and distorts much earlier as you turn up the volume.

#21 BoomboxLover48

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Posted 12 January 2017 - 10:13 PM

 

There are blue caps, you can see them in this pic. Honestly the sound is mostly mids and mid-bass. Nothing deep, nothing very high. Also, this one was sold in Germany and it doesn't have a separate Loudness switch (the Loudness is supposedly integrated into the Volume circuit), so maybe that's part of the reason.

WP_20170109_13_29_27_Pro.jpg


I would at least remove the foam that's obstructing the bass ports . On a ported box if the vents are blocked even the slightest bit it will have a tremendous effect on the sound.if anything I would remove it all together and replace it with a small amount of poly fill.

 

Very correct!

 

Foam will interfere with the air movement.

 

Acoustic damping tiles or other materials can be used for sound absorption. Damping is done by making the internal surface not to reflect sound and absorb it. 



#22 Reli

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Posted 13 January 2017 - 09:23 AM

I removed it, and the sound still sucks....no bass.  So either my amps are dead, or the woofers are cheap garbage.

 

You want warm bass, you need a Telefunken.  And BTW that box is sealed, not ported!



#23 Reli

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Posted 11 August 2017 - 02:04 PM

Still trying to find out what's wrong with this unit.  Anyone know why the cap that goes to the tweeter would be grounded to the speaker frame?  Never seen that before.  Mistake?

:huh:

 

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#24 JVC Floyd

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Posted 11 August 2017 - 04:25 PM

Honestly I would bypass those caps and see what it sounds like, I'm not sure why it would be grounded to the speaker frame I would think that would short circuit and stop the sound all together.

#25 jimmyjimmy19702010

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Posted 11 August 2017 - 05:24 PM

Normal. Speaker baskets aren't electrically connected to the speaker terminals.

#26 Reli

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Posted 11 August 2017 - 08:11 PM

Normal. Speaker baskets aren't electrically connected to the speaker terminals.

 

Yours are wired the same? 



#27 jimmyjimmy19702010

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Posted 11 August 2017 - 08:35 PM

Normal. Speaker baskets aren't electrically connected to the speaker terminals.

 
Yours are wired the same?
Yep

#28 caution

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Posted 12 August 2017 - 12:30 AM

Reli, I opened the back of one of my 9150W speakers to check the wiring.

 

Usually you have a terminal strip riveted to the woofer in dual speaker cabinets with a crossover cap for the tweeter, and it almost always has a third terminal that serves as a tie point for the output side of the cap, and the wire that feeds it to the tweeter.

 

But the speakers in these units don't have one so Hitachi used the woofer frame instead, which is isolated.

 

35706253473_d0bb5fcacf_k.jpg



#29 Superduper

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Posted 12 August 2017 - 10:36 PM

Eric is right. On most boomboxes, the high pass capacitor leads are soldered onto a 3-terminal terminal-strip. But hitachi was too cheap to rivet one of those onto the speaker frame or cabinet so they just used the speaker frame for the 3rd mounting leg. The problem is that the speaker frame is a large target and splicing a connection there makes that a large "live" target. Any stray wire or ground could conceivably short out the amp, especially on a 1-pc box. Imagine doing live test and have something drop onto the speaker frame! Luckily, this is a 3-pc'er and is probably safe.

Now another observation is that it appears that there is a 1.5uf cap being used as a high pass cap. Wait.... what??? I hope that is an 8-ohm tweeter, otherwise if that is a 4-ohm (or less driver), it appears that it would crossover at 26.5khz. If 8-ohm tweeter, it is a far more reasonable 13khz +/-. However, an 8-ohm tweeter being mated with 3.2 ohm woofs means might could render the tweeter too subtle and overpowered by the woofers. Perhaps this is why Reli noticed not great highs?

#30 Reli

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Posted 12 August 2017 - 11:19 PM

Thanks guys! Mine do have a terminal riveted to the speaker as you can see in my pic, but it's just 2-terminal.

 

Yes it's an 8 ohm tweeter and a 1.5 cap.  Specifically they are labeled Nicon 1.5MFD63WV

 

The channels are even, the switches are static-free, but there's no bass at all.  So I'm guessing either they used different amps on mine, or they've gone bad.  Eric do you know the amp code number, and is it 1 or 2 chips?