New Member, Intro, Hitachi HMA-8300 assistance needed.

[Erictator]

Hi -

Guess I should introduce myself first. I'm an enthusiast, have rebuilt some tube audio equipment, can read a schematic, but am a bit rusty. Many moons ago I was a TV bench tech, mostly tube sets at a place that refurbed and sold used TV's. Not much experience in solid state amps, but am anxious to learn.

Current main 2 channel system includes various input devices, using the preamp out of my Scott 299b to a Carver PM-175 to a pair of EnergyRefCon 22's. Also have the Scott directly driving a pair of high efficiency Jensen 15" 3way with horns.

Picked up a non working unit, Hitachi HMA-8300 Series E. Got it from a local guy cheap enough to play with. Have to admit, the huge power transformer, enormous Caps and big meters on the front made me really want this thing. I'm guessing these sound pretty good???? Waiting on a schematic from of those download sites... then found this forum.

The guy I bought the unit from said it powered up, but no audio. I thought maybe it was going into protection, so I brought it up slowly on my variac. Whoops! That only seemed to delay protection long enough to smoke a "fuse-resistor". Maybe it was already partially smoked before? Anyways, it's on the right channel, and don't think that would bring down both channels, would it? I'm guessing there's probably other issues... the Meters do light up, but no output from either channel.

Anyone familiar with these amps that could offer some experience or tips for trouble shooting would be most welcome. Might save me some grief.

Thanks in advance for any & all replies.


Eric

 

[gunsoftexas]

Schematic?

You could look HERE

Just a little tip for you folks searching the net for schematics:

Try model number
Then try model number + pdf in Google search
ex: HMA-8500 pdf

or try model number + (the word) schematic
ex: HMA-8500 schematic

Good luck and happy audio daze to yee all!

 

[gunsoftexas]

8300~8500 !@#&?

I assume the 8500 will help with your 8300 woes. I realize it is not the fully desired result but it just may do?

Keep 'em in yer holsters, at least until high noon.

 

[Erictator]

Thanks, that's pretty close in some areas, but not a match in others. I finally had the manual come in that I ordered. Gonna need a magnifier glass or take it to Kinko's to enlarge this thing to read the schematic!!! Eeeek!

Thanks again,
Eric

 

[poetry2me]

OK now, THIS IS YEARS LATER and I really don't know if you are still interested but ...

I just finished fixing or better "restauring" a badly mis-repaired HMA-8300 myself. It took months.

The good news is I documeted everything in a forum, with lots of pictures and backgrounds.
The bad news could be that it is all in German.
http://www.hifi-forum.de/index.php?action=browseT&forum_id=185&thread=7185

Just one remark:
After repair, some friends and I made a listening test with the HMA-8300 and it really sounded amazing

Anyway, feel free to contact me or ask here.
I admit I am also just curious about the fate of you amp.

- Poetry2me