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I never thought much of their transistor amps,
on repairing this unit. If the STK is bad, a new one can be obtainedOn Thursday, April 18, 2019 at 8:01:25 PM UTC-4, tub...@myshop.com wrote:
Is there any way to test a STK463 Audio Amp chip? (without having some
sort of special factory analyzer)?
I had a Marantz SR1000 receiver given to me. I plugged it in, and got a
few seconds of hum, panel lights dimmed also. Then smoke appeared. I
found the source of the smoke, a small electrolytic cap blew, and left
the board wet.
I may try to replace that cap, but I suspect there is more wrong. I dont
usually work on anything containing IC chips. And Im sure if that big
amp chip is bad, it would be very costly. (Not worth my time or money).
But I'd be willing to test it if I know how.
By the way, the power supply is working. As soon as I unplugged it
(after the smoke), I got a good spark when I shorted the main (large)
filter caps.
Please post the cap that smoked. Its location will help us to provide guidance
On Thu, 18 Apr 2019 19:18:22 -0700 (PDT), dansabrservices@yahoo.com
wrote:
On Thursday, April 18, 2019 at 8:01:25 PM UTC-4, tub...@myshop.com wrote:
Is there any way to test a STK463 Audio Amp chip? (without having some
sort of special factory analyzer)?
I had a Marantz SR1000 receiver given to me. I plugged it in, and got a
few seconds of hum, panel lights dimmed also. Then smoke appeared. I
found the source of the smoke, a small electrolytic cap blew, and left
the board wet.
I may try to replace that cap, but I suspect there is more wrong. I dont
usually work on anything containing IC chips. And Im sure if that big
amp chip is bad, it would be very costly. (Not worth my time or money).
But I'd be willing to test it if I know how.
By the way, the power supply is working. As soon as I unplugged it
(after the smoke), I got a good spark when I shorted the main (large)
filter caps.
Please post the cap that smoked. Its location will help us to provide guidance
on repairing this unit. If the STK is bad, a new one can be obtained
for $10-$15.
Dan
The blown cap is C807. Its.connected in the area of the Q805 transistor,
which I am guessing is a voltage regulator (maybe)???? Appears to be
10uf at 50v.
I have not found a schematic for this unit so I'm in the dark on it....
But this is in the power supply area.
I have watched several videos on YT about similar units that use the STK
modules. It seems they work well, until they fry. Then all hell breaks
out. The other caution is that many of the after market STK mods are
fakes, which do not work.
I will also mention that in the 80's, I worked on a Fisher stereo that
had a STK mod. Back then these mods were costly. I bought a replacement,
it burned up instantly. (And yes I had checked power supply voltages and
all of that before powering it up). Theres a video on YT in which some
guy had the same experience. On that one I worked on in the 80s, I spent
many hours, and lost a lot of money on it. Actually, that was when I
quit working on other peoples gear.
I ended up stuffing a amplifier board inside that stereo, from another
device, just so I could hand the owner a working stereo. It worked but
only produced around 5watts per channel. The owner was satisfied, but
not highly impressed by the low power.
Needless to say, I do not have a very good impression of those STK
modules, overall.
Aside from that, since this thing cost me nothing, I'll play around with
it, and will stick a few bucks in it for caps and such. After that it
will just become a pile of salvagable parts...... While its a nice
looking device, its not worth much effort or money to me.
Note: Before posting this i did find a schematic.....
tabby wrote:
** I gave up all interest in working for hi-fi importers when I heard that 90% of the work was in fixing damn cassette decks. Although I have worked on a few for regular customers, I have never owned one.
However, I did buy a Brenell RR transport fitted with "Sonic" heads from Geoff at RDS in the late 1970s. Built all the necessary electronics and had it working nicely - the goal being to record live music broadcasts from 2MBS FM.
Unfortunately, even at 15ips the loss of quality was too great for my liking and I also found the same thing when I tried a Teac 1/4 inch half track in the role. Modulation noise, tape hiss and loss of definition ( IM distortion ?) were all too evident. Mind you, I was listening via Quad ESLs..
The only tape recorder that came close was a VHS Hi-Fi video loaned to me by a customer. That could copy an all digital CD of classical piano with negligible loss. Funny how they never caught on as audio recorders.
Consumers all seem to prefer convenience over sound quality.
.... Phil
Yes - there were several better cassette formats than compact cassette,
but CC is what won.
** A massive irrelevance.
NT
** NT = Nutcase Thornton serial pest and troll
..... Phil
"Unfortunately when they transistorised around '70 their quality dropped through the floor. "
My buddy's AU-9500 begs to differ.
We seem to have old wine in a new bottle.
https://www.dropbox.com/s/b2kxpmmwwgb5syz/GoogleEarth_Image.jpg?dl=0
I wonder if our resident Tourette's victim lives behind that small black door, or not? Looks like a good place to store trash.
On 23/4/19 2:37 am, pfjw@aol.com wrote:
We seem to have old wine in a new bottle.
https://www.dropbox.com/s/b2kxpmmwwgb5syz/GoogleEarth_Image.jpg?dl=0
I wonder if our resident Tourette's victim lives behind that small
black door, or not? Looks like a good place to store trash.
Guess again. My auto electrician is up that ramp off Pittwater Rd, but
it's a long way from PA's house.
.
**Yup. That would be the address of Allison Audio, owned and operated by
David Allison. Completely different person.
it burned up instantly. (And yes I had checked power supply voltages and
all of that before powering it up).
Where does the model 2230 fall in this lineup? I still have one ofOn 19/04/2019 7:21 pm, pallison49@gmail.com wrote:
Trevor Wilson wrote:
Back when I was service manager for Marantz
Australia, I replaced a hundred or so of the things.
** I thought " Service Managers " let others do the soldering iron
jockeying?
**When I first started, I had a junior tech to do the work I didn't
like. That said, when I started there, I had no experience with cassette
decks and he did. I was able to learn quite a bit from him. About a year
later, the company ran into financial difficulties and they sacked my
junior tech. Another year passed and the company hired another tech for
me to boss around. I also got a full time spare parts lady.
Not so reliable, but easy to replace.
** Trouble is the part is not internally current or VI limited, so not
short circuit proof, relying on DC rail fuses instead.
Reliable enough, long as the user is careful with speaker wiring and
such.
**Correct. It was what Marantz called: "value engineering". Up 'till the
SR range, all Marantz receivers and amplifiers employed excellent VI
limiting systems, along with discrete transistor output stages and full
steel construction. When the boss excitedly told me about this "value
engineering" malarky, I grew suspicious. When I saw the result, I was
profoundly disappointed. It was crap. Timber top covers and, in some
cases, Masonite base plates. Urk. Lousy heat dissipation. Gone was the
beautiful backlit dials. It was so sad. Marantz was then (partly) sold
to Philips. Philips actually improved things considerably and the SR
series was consigned to the dustbin of history.
On 4/19/19 3:23 AM, Trevor Wilson wrote:
On 19/04/2019 7:21 pm, pallison49@gmail.com wrote:
Trevor Wilson wrote:
Back when I was service manager for Marantz
Australia, I replaced a hundred or so of the things.
** I thought " Service Managers " let others do the soldering iron
jockeying?
**When I first started, I had a junior tech to do the work I didn't
like. That said, when I started there, I had no experience with
cassette decks and he did. I was able to learn quite a bit from him.
About a year later, the company ran into financial difficulties and
they sacked my junior tech. Another year passed and the company hired
another tech for me to boss around. I also got a full time spare parts
lady.
Not so reliable, but easy to replace.
** Trouble is the part is not internally current or VI limited, so
not short circuit proof, relying on DC rail fuses instead.
Reliable enough, long as the user is careful with speaker wiring and
such.
**Correct. It was what Marantz called: "value engineering". Up 'till
the SR range, all Marantz receivers and amplifiers employed excellent
VI limiting systems, along with discrete transistor output stages and
full steel construction. When the boss excitedly told me about this
"value engineering" malarky, I grew suspicious. When I saw the result,
I was profoundly disappointed. It was crap. Timber top covers and, in
some cases, Masonite base plates. Urk. Lousy heat dissipation. Gone
was the beautiful backlit dials. It was so sad. Marantz was then
(partly) sold to Philips. Philips actually improved things
considerably and the SR series was consigned to the dustbin of history.
Where does the model 2230 fall in this lineup? I still have one of
those, bought in about 1970, I think...still worked last time I powered
it on...several years ago.
On 4/19/19 3:23 AM, Trevor Wilson wrote:
On 19/04/2019 7:21 pm, pallison49@gmail.com wrote:
Trevor Wilson wrote:
Back when I was service manager for Marantz
Australia, I replaced a hundred or so of the things.
** I thought " Service Managers " let others do the soldering iron
jockeying?
**When I first started, I had a junior tech to do the work I didn't
like. That said, when I started there, I had no experience with cassette
decks and he did. I was able to learn quite a bit from him. About a year
later, the company ran into financial difficulties and they sacked my
junior tech. Another year passed and the company hired another tech for
me to boss around. I also got a full time spare parts lady.
Not so reliable, but easy to replace.
** Trouble is the part is not internally current or VI limited, so not
short circuit proof, relying on DC rail fuses instead.
Reliable enough, long as the user is careful with speaker wiring and
such.
**Correct. It was what Marantz called: "value engineering". Up 'till the
SR range, all Marantz receivers and amplifiers employed excellent VI
limiting systems, along with discrete transistor output stages and full
steel construction. When the boss excitedly told me about this "value
engineering" malarky, I grew suspicious. When I saw the result, I was
profoundly disappointed. It was crap. Timber top covers and, in some
cases, Masonite base plates. Urk. Lousy heat dissipation. Gone was the
beautiful backlit dials. It was so sad. Marantz was then (partly) sold
to Philips. Philips actually improved things considerably and the SR
series was consigned to the dustbin of history.
Where does the model 2230 fall in this lineup? I still have one of
those, bought in about 1970, I think...still worked last time I powered
it on...several years ago.
Just don't break the dial string. You said way back you had trouble with cassette decks ? Well I got one trouble and that is dial stringing. I wish there was a guy around I could just pay to do it.
"**The 2230 is old school Marantz. Very nicely laid out, easy to service and TO3 output devices. Should last a very, very long time. The smaller receivers of the time used plastic pack output devices and were significantly less reliable than those (like the 2230) that employed TO3 output devices. "
Just don't break the dial string. You said way back you had trouble with cassette decks ? Well I got one trouble and that is dial stringing. I wish there was a guy around I could just pay to do it.
"**The 2230 is old school Marantz. Very nicely laid out, easy to service and TO3 output devices. Should last a very, very long time. The smaller receivers of the time used plastic pack output devices and were significantly less reliable than those (like the 2230) that employed TO3 output devices."
Just don't break the dial string. You said way back you had trouble with cassette decks ? Well I got one trouble and that is dial stringing. I wish there was a guy around I could just pay to do it.