Soldering job in my HT Reciever

[moe29]

My Home Theatre Receiver quit working the other day, so tonight
i took a the top off to take a look inside, see if it was just a fuse
that needed replacing. (not the case) and happened to take a
look at the output devices... i was shocked at the crap soldering
job. see attached pics. Wasn't sure if i should name the brand,
but will if anyone is interested. It's a 5 to 6 year old piece. What
do you guys think?

[moe29]

another view

[Tube_Dude]

Hi Moe...

Are you sure that this transistors are the originals and not some one upgrade or reparation...

PS: It look like HK...

[moe29]

yeah, it's never left my house since the day i opened the factory
box... it looks like maybe the chips were just off alignment a little
when they were soldered? I'm sure this is automated work, not
done by hand... (actually i have no idea!) maybe this is pretty
much the norm for mass production...

[Tube_Dude]

HI

It is not very good practice to left the PC board with rosin flux...definitely not a very clean and reliable job!!

[moe29]

i thought it was strange to see the IC pins just laying on top of
the PC board like that... i thought they'd be through hole at least.

[Tube_Dude]

i thought it was strange to see the IC pins just laying on top of the PC board

It's not the IC pins...it's the output transistors pins...

[moe29]

ooops! (been a long day)

these transistors are Toshiba 2SA1302 & 2SC3281 per channel

...doing a little Google search, these seem to be very common
devices for the time of production, since discontinued. Notice the
crap trim pot? Reading on TNT-Audio - Cheap trim pots tend to
have deteriorating contacts, offsetting amplifiers and degrading
their original performance over time. interesting.

oh well... i guess i'm going to have to find a service center to see
if they can figure out why it quit working. (i know it's not the stuff
i've pointed out, just thought it was interesting to show some pics)

[Duo]

That certainly doesn't look like a typical factory job. They usually at least clean the flux off.

It is normal to see transistors soldered on the side of the board and not through-hole in some amps. It doesn't really mean bad quality and I think it's actually a better connection since there's more surface area contact between the lead and the trace on the board than in through-hole practice.

Would you care to mention the brand of the amp? It reminds me of probably a Sanyo, but the ones I've seen had better soldering under the hood.

[moe29]

ONKYO TX-SV919THX circa 1996 (if i'm remembering right)
first HT Receiver to be THX certified. 100w x 3 & 50w x2.

((i can't believe i've had it that long!))