Is there any way to test a STK463 Audio Amp chip?

[tub...@myshop.com]

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.

[Trevor Wilson]

On 19/04/2019 10:01 am, tub...@myshop.com wrote:
> Is there any way to test a STK463 Audio Amp chip? (without having some
> sort of special factory analyzer)?

**Yep. Download a data sheet, build up the test circuit and test.
Alternatively, plug it into the existing product, crank the unit up on a
variable auto-transformer (aka: Variac™). Watch Voltages and currents
carefully.

>
> 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.

**Which cap? You could analyse the circuit and determine what is causing
the cap to fail (assuming it is not just the cap).

>
> 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.

**"Big money"?!! Are you serious? They're like 10 Bucks. 10 minutes of
your time (using a vacuum desolder iron, or 20 minutes with a manual
one), job done. Easy-peasy. Back when I was service manager for Marantz
Australia, I replaced a hundred or so of the things. Not so reliable,
but easy to replace. No fault-finding required.

>
> 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.

**Yeah, no. That ain't real smart either.


--
Trevor Wilson
www.rageaudio.com.au

---
This email has been checked for viruses by Avast antivirus software.
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[dansabr...@yahoo.com]

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

[tub...@myshop.com]

On Thu, 18 Apr 2019 19:18:22 -0700 (PDT), dansabr...@yahoo.com
wrote:

Will post it when i am back at the shop. I am currently looking for a
schematic to download. Thus far im not finding any.

Thanks

[palli...@gmail.com]

tub...@myshop.com wrote:

>
>>
> Will post it when i am back at the shop. I am currently looking for a
> schematic to download. Thus far im not finding any.
>
>

** FFS use Google.com and " STK463 schem "

Wot a pathetic retard.



.... Phil

[Trevor Wilson]

**You're kidding, right? What planet do you live on?

Try here:

https://www.hifiengine.com/manual_library/marantz/sr1000.shtml

Or, for the STK463, here:

https://www.datasheetspdf.com/datasheet/STK463.html

So, do you have the internet there on Mars?

[palli...@gmail.com]

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?

> 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.



... Phil

[Trevor Wilson]

On 19/04/2019 7:21 pm, palli...@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.

[tabb...@gmail.com]

Sansui similarly suicided. From excellent to junk.

[peterw...@gmail.com]

> Sansui similarly suicided. From excellent to junk.

Sansui had many things. Lots o' buttons, lots o' knobs, reasonably good build-quality, but absolutely NOTHING to raise its brand above any other contemporary brand from the Pacific Rim. One more jellybean in the bowl distinguishable only by its surface color.

Peter Wieck
Melrose Park, PA

[tabb...@gmail.com]

On Friday, 19 April 2019 15:56:20 UTC+1, pf...@aol.com wrote:
NT:

That's odd. As I recall Sansui valve amps had excellent sound quality, not great build quality but good enough, and certainly not lots of knobs or buttons. Unfortunately when they transistorised around '70 their quality dropped through the floor.


NT

[peterw...@gmail.com]

On Friday, April 19, 2019 at 12:08:22 PM UTC-4, tabb...@gmail.com wrote:

> That's odd. As I recall Sansui valve amps had excellent sound quality, not great build quality but good enough, and certainly not lots of knobs or buttons. Unfortunately when they transistorised around '70 their quality dropped through the floor.

And, perhaps, the worst output transformers on the planet at the time, competing with, but not quite as bad as Kenwood. That was their downfall on the tube side. The solid-state side, as previously described.

Their OPTs were known for lots of, but flabby bass, and not much, but sibilant treble.

[tabb...@gmail.com]

On Friday, 19 April 2019 17:35:19 UTC+1, pf...@aol.com wrote:

The one I had gave the Quad II a very good run for its money. Perhaps your comments apply to some earlier model. Their downfall was the excessive voltage used on the valves, 500v on 7189A IIRC. That & the unavailability of 7189A is why they aren't a recommended buy now.


NT

[peterw...@gmail.com]

On Friday, April 19, 2019 at 1:39:13 PM UTC-4, tabb...@gmail.com wrote:
> The one I had gave the Quad II a very good run for its money. Perhaps your comments apply to some earlier model. Their downfall was the excessive voltage used on the valves, 500v on 7189A IIRC. That & the unavailability of 7189A is why they aren't a recommended buy now.

I will spare you my opinion on Quad tube stuff. And, as it happens, their equipment from start-to-finish is vastly overrated - but for a few of their ESL speakers. Operative word being 'few'.

c.f.: Blind squirrels and nuts.

But, that is why there are many flavors of ice cream, and even sherbets for the lactose-intolerant.

[palli...@gmail.com]

pf...@aol.com wrote:

** the resident fuckwit on this nG

>
> I will spare you my opinion on Quad tube stuff.
>

**Thank god for that - now if the retarded nincompoop would just od the same with every other topic.

> And, as it happens, their equipment from start-to-finish is vastly overrated

** No Mr Weeky, YOU are vastly overrating your pig ignorant opinions.

Cos you are raving nut case of the worst possible kind.



.... Phil

[palli...@gmail.com]

Trevor Wilson wrote:

>
> >
> > ** 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.
>
>
>

** 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

[tabb...@gmail.com]

On Saturday, 20 April 2019 01:35:42 UTC+1, palli...@gmail.com 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.


NT

[tabb...@gmail.com]

On Friday, 19 April 2019 19:54:13 UTC+1, pf...@aol.com wrote:

I never thought much of their transistor amps, but the II power amp was rather nice (the 22 preamp sold with them not so much) and I still wonder why I sold the ESLs.


NT

[Fox's Mercantile]

On 4/19/19 7:35 PM, palli...@gmail.com wrote:
> Consumers all seem to prefer convenience over sound quality.

.mp3 is proof of that.


--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

[palli...@gmail.com]

** A massive irrelevance.

>
> NT

** NT = Nutcase Thornton serial pest and troll



..... Phil

[palli...@gmail.com]

tabb...@gmail.com wrote:

>
>
>
> I never thought much of their transistor amps,
>

** Retards NT never think much about anything.

but the II power amp was rather nice

** I have one as my bench amp, its meets original specs after a rebuild including a mid band THD of under 0.05%.



.... Phil

[tub...@myshop.com]

On Thu, 18 Apr 2019 19:18:22 -0700 (PDT), dansabr...@yahoo.com
wrote:

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.....

[Trevor Wilson]

**Do you see my posts? Again:


https://www.hifiengine.com/manual_library/marantz/sr1000.shtml

>
> 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.

**Although I've not seen any, that wouldn't surprise me.

>
> 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.

**I have quite a bit of experience with them. On the whole, they're OK.
Some are better than others though.

>
> 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.....
>

**So you DID read my posts up there on Mars?

[tabb...@gmail.com]

On Saturday, 20 April 2019 03:55:00 UTC+1, palli...@gmail.com wrote:

If only you hadn't been dropped on your head.


NT

[jurb...@gmail.com]

>"Unfortunately when they transistorised around '70 their quality dropped through the floor. "

My buddy's AU-9500 begs to differ.

[tabb...@gmail.com]

On Monday, 22 April 2019 00:54:12 UTC+1, jurb...@gmail.com wrote:

> >"Unfortunately when they transistorised around '70 their quality dropped through the floor. "
>
> My buddy's AU-9500 begs to differ.

that looks massively better than their earlier 70s junk I've seen. They really destroyed their rep with that stuff.


NT

[jurb...@gmail.com]

>"Consumers all seem to prefer convenience over sound quality. "

Not all, trust me on that.

[peterw...@gmail.com]

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.

[Clifford Heath]

On 23/4/19 2:37 am, pf...@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.

[Trevor Wilson]

**Yup. That would be the address of Allison Audio, owned and operated by
David Allison. Completely different person.

[palli...@gmail.com]

Trevor Wilson wrote:

> .
> >
>
> **Yup. That would be the address of Allison Audio, owned and operated by
> David Allison. Completely different person.
>
>

** Not a relative either.


.... Phil

[mako...@yahoo.com]

. 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).

You need to learn the technique of using a Variac or a light bulb in series with the AC input to test before applying full power.

m

[Bill Martin]

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.

[jurb...@gmail.com]

Let me set this to rest. That IC has + and - inputs. Treat it like an OP AMP.

Know how to troubleshoot an OP AMP ? this is the same thing only bigger. It also might have booststrap caps and maybe some bypass, but even without them it should kinda work.

[Trevor Wilson]

**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.

[Chuck]

On Thu, 25 Apr 2019 11:09:09 -0700, Bill Martin <w...@wwmartin.net>
wrote:

It is a pretty decent receiver. It wasn't made by Marantz in the U.S..
It was manufactured by Standard Radio in Japan.

[jurb...@gmail.com]

>"**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.

[peterw...@gmail.com]

On Friday, April 26, 2019 at 1:05:48 PM UTC-4, jurb...@gmail.com wrote:

> 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.

Invest in a couple of small hemostats, some curved suture needles (coarse) and a couple of dental picks. Buy a box of small springs from McMaster-Carr, and you will find your life to be much easier. That, and some Dacron fishing line of the correct gauge (does not stretch and holds very tight knots very well) - simple.

[John-Del]

On Friday, April 26, 2019 at 1:05:48 PM UTC-4, jurb...@gmail.com wrote:

> >"**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.

My dad hated dial cord stringing. When he got married in the 1940s and opened up a radio repair shop, he had my mom string up radios which she did with no trouble at all. She could also knit, sew, crochet, and make ravioli so good that you would cry.

I just restrung one of those "Crosley" radio/phono/cd abominations and it looks like it was designed wrong. One of the pulleys was on the far side of the main tuner pulley and very close to it. There was no way that would have worked easily with the dial cord pulled over the top of the main pulley in the opposite direction. It didn't even function as a back tension pulley to keep the lateral pull on the tuner even. I shortened the dial cord leaving the odd pulley out and it worked easily and smoothly and in the correct direction with only two turns on the tuning shaft.

[Trevor Wilson]

On 27/04/2019 3:05 am, jurb...@gmail.com wrote:
>> "**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.
>

**I broke a few in the early days. Once bitten, twice shy. I haven't
damaged one since. PITA to repair.