I've got an old Technics SA-R210 stereo receiver from the 80's which I've relied
on for ages.

Woke up this morn and it played for a while, then silence. Powered down,
let it sit 10 min., powered up and it worked again for 15 min., then silence.

Receiver is in a cabinet with little ventilation. Obviously likely to be a
heat related problem.

Does this suggest a particular component? I can bench-test, solder a little.
How difficult to repair DIY??

Thx,
P

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."

On Aug 17, 10:55*am, Puddin' Man wrote:
I've got an old Technics SA-R210 stereo receiver from the 80's which I've relied
on for ages.

Woke up this morn and it played for a while, then silence. Powered down,
let it sit 10 min., powered up and it worked again for 15 min.,
then silence.

Receiver is in a cabinet with little ventilation. Obviously likely
to be a
heat related problem.

Does this suggest a particular component? I can bench-test, solder
a little.
How difficult to repair DIY??

* Thx,
* P

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."

I have one of those and an SA-160. The 160 had a problem with cracked
solder joints on voltage regulator transistors on the main heatsink.
The 160 is a little odd to disassmble and I think the 210 is similar.
Got a digital camera? take lots of pics as you open it up so you can
get it back. You _might_ have a thermally intermittent power regulator
but bad (metal fatigue) solder is far more common.

G²

On Tue, 17 Aug 2010 18:49:18 -0700 (PDT), wrote:

I have one of those and an SA-160. The 160 had a problem with cracked
solder joints on voltage regulator transistors on the main heatsink.
The 160 is a little odd to disassmble and I think the 210 is similar.
Got a digital camera?

Yup.

take lots of pics as you open it up so you can
get it back.

Will do.

You _might_ have a thermally intermittent power regulator
but bad (metal fatigue) solder is far more common.

Not sure when I'll be able to get to it. Too many irons
in the fire ...

So ... find the big heatsink. Voltage regulator is on
this unit? Remove regulator cover to find transistors and
possibly cracked joints??

Much Thanks,
P

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."

Hi!

Receiver is in a cabinet with little ventilation. Obviously likely to be a
heat related problem.

You should move it to a place where it can get better ventilation. Some of
these run quite hot.

Is this receiver losing power totally, or do some functions (like the
display and tuning buttons) continue to work? If it does, I'd bet that it's
going into protection to save your speakers from a disaster. Most--if not
all--of these units used Sanyo hybrid audio amplifier ICs (a large
many-legged black thing) and I think it's safe to say those were the weakest
point of them. They don't like heat and it seems like Technics skimped on
the heatsink in many of these units.

William

"Puddin' Man" wrote in message
...
On Tue, 17 Aug 2010 18:49:18 -0700 (PDT), wrote:

I have one of those and an SA-160. The 160 had a problem with cracked
solder joints on voltage regulator transistors on the main heatsink.
The 160 is a little odd to disassmble and I think the 210 is similar.
Got a digital camera?

Yup.

take lots of pics as you open it up so you can
get it back.

Will do.

You _might_ have a thermally intermittent power regulator
but bad (metal fatigue) solder is far more common.

Not sure when I'll be able to get to it. Too many irons
in the fire ...

So ... find the big heatsink. Voltage regulator is on
this unit? Remove regulator cover to find transistors and
possibly cracked joints??

Much Thanks,
P


No covers over the transistors, just bolted straight to the heatsink and
should be visible once the unit's case is off. Cracked-right-round joints on
any heatsink mounted devices are very common on Technics. Most models not
too bad to strip to the point where you can get to the underside of the
board. As the other poster said, take pics if not confident that you can
remember where all the screws go back.

Arfa

On Aug 18, 5:52*pm, "William R. Walsh"
m wrote:
Hi!

Receiver is in a cabinet with little ventilation. Obviously
likely to be a
heat related problem.

You should move it to a place where it can get better ventilation.
Some of
these run quite hot.

Is this receiver losing power totally, or do some functions (like
the
display and tuning buttons) continue to work? If it does, I'd bet
that it's
going into protection to save your speakers from a disaster. Most--
if not
all--of these units used Sanyo hybrid audio amplifier ICs (a large
many-legged black thing) and I think it's safe to say those were
the weakest
point of them. They don't like heat and it seems like Technics
skimped on
the heatsink in many of these units.

William

A properly operating SA-R210 idles at a very modest temperature.
Obviously it warms up if delivering serious power but by and large the
heat output is pretty modest - certainly not above average.

I just checked the service manual for the 210 and it does mount the
regulator transistors on the main heatsink flanking the main audio
power IC. Q705 reduces the -48 to -19.7. Q701 and 702 are in parallel
to drop the +48 to +15.6. Note that there are regulators following
these to achieve -13.9, +15.5 (capacitor multiplier) and +5.7 for the
microprocessor (using another diode to get to +5V).

On the similar SA-160 which has 2 regulator transistors on the main
heat sink, all 6 terminals were cracked loose. After re-soldering
those I unsoldered the main power IC and resoldered it too since it is
mounted the same way as the transistors. Surprisingly, none of the
foil pads were damaged.

On my R210 the solder connections under the volume raise / lower
buttons cracked making the buttons flaky. Re-soldering them left it
working perfectly again. No bad pads on this unit either.

G²

On Wed, 18 Aug 2010 19:52:15 -0500, "William R. Walsh"
m wrote:

Hi!

Receiver is in a cabinet with little ventilation. Obviously likely to be a
heat related problem.

You should move it to a place where it can get better ventilation. Some of
these run quite hot.

I pulled the shelf above to give it more room. Put a little fan on
a stand, directed flow to the chassis vents. Ran for maybe a couple
hours before audio failed again.

Is this receiver losing power totally, or do some functions (like the
display and tuning buttons) continue to work?

The front display panel remains lighted. Looks normal but no sound.
Jiggling wires has no effect.

If it does, I'd bet that it's
going into protection to save your speakers from a disaster. Most--if not
all--of these units used Sanyo hybrid audio amplifier ICs (a large
many-legged black thing) and I think it's safe to say those were the weakest
point of them. They don't like heat and it seems like Technics skimped on
the heatsink in many of these units.

Could be for all I know. I'll put the unit on my work-bench today, take a
closer look.

I actually have 2 SA-R210 receivers. Both have problems. The other one,
with bad power switch and maybe cracked audio output joints, has been
pressed into service.

Thx,
P

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."

On Wed, 18 Aug 2010 22:21:21 -0700 (PDT), wrote:
...
point of them. They don't like heat and it seems like Technics
skimped on
the heatsink in many of these units.

William

A properly operating SA-R210 idles at a very modest temperature.
Obviously it warms up if delivering serious power but by and large the
heat output is pretty modest - certainly not above average.

This is consistent with my experience with them. I've been running
mine 15-16 hours/day for about the last 10 years.

I just checked the service manual for the 210 and it does mount the
regulator transistors on the main heatsink flanking the main audio
power IC. Q705 reduces the -48 to -19.7. Q701 and 702 are in parallel
to drop the +48 to +15.6. Note that there are regulators following
these to achieve -13.9, +15.5 (capacitor multiplier) and +5.7 for the
microprocessor (using another diode to get to +5V).

I am finding Q705, Q701 and 702 markings and the regulator transistors
etc on the main board/heatsink, no problem.

On the similar SA-160 which has 2 regulator transistors on the main
heat sink, all 6 terminals were cracked loose. After re-soldering
those I unsoldered the main power IC and resoldered it too since it is
mounted the same way as the transistors. Surprisingly, none of the
foil pads were damaged.

If you could render just a rough break-down of what was involved
in resoldering the regulator transistors, it might well enable
me to repair this unit.

On my R210 the solder connections under the volume raise / lower
buttons cracked making the buttons flaky. Re-soldering them left it
working perfectly again. No bad pads on this unit either.

I am:

a.) A relative bonehead re detailed electronic repairs.
b.) Willing to learn. Retired, with a house-full of electronic stuff.
Much of it can't be replaced, something breaks most every day.

I can post pics if it would be helpful.

Thx,
P

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."

On Aug 19, 12:41*pm, Puddin' Man wrote:
On Wed, 18 Aug 2010 22:21:21 -0700 (PDT), wrote:

*...

point of them. They don't like heat and it seems like Technics
skimped on
the heatsink in many of these units.

William

A properly operating SA-R210 idles at a very modest temperature.
Obviously it warms up if delivering serious power but by and large the
heat output is pretty modest - certainly not above average.

This is consistent with my experience with them. I've been running
mine 15-16 hours/day for about the last 10 years.

I just checked the service manual for the 210 and it does mount the
regulator transistors on the main heatsink flanking the main audio
power IC. Q705 reduces the -48 to -19.7. Q701 and 702 are in parallel
to drop the +48 to +15.6. Note that there are regulators following
these to achieve -13.9, +15.5 (capacitor multiplier) and +5.7 for the
microprocessor (using another diode to get to +5V).

I am finding Q705, Q701 and 702 markings and the regulator transistors
etc on the main board/heatsink, no problem.

On the similar SA-160 which has 2 regulator transistors on the main
heat sink, all 6 terminals were cracked loose. After re-soldering
those I unsoldered the main power IC and resoldered it too since it is
mounted the same way as the transistors. Surprisingly, none of the
foil pads were damaged.

If you could render just a rough break-down of what was involved
in resoldering the regulator transistors, it might well enable
me to repair this unit.

On my R210 the solder connections under the volume raise / lower
buttons cracked making the buttons flaky. Re-soldering them left it
working perfectly again. No bad pads on this unit either.

I am:

a.) A relative bonehead re detailed electronic repairs.
b.) Willing to learn. Retired, with a house-full of electronic stuff.
* * Much of it can't be replaced, something breaks most every day.

I can post pics if it would be helpful.

* Thx,
* P

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."

A simple voltmeter can give a lot of information particularly while
it's in 'failed' mode. While power devices (transistors and the main
audio power IC) can go 'thermal, I haven't seen a thermally sensitive
transistor in many years. The most common way back when was the TO-220
case devices - just like Q 701,702 and 705 but I would put money on
bad solder joints.

G²

On Thu, 19 Aug 2010 19:51:55 -0700 (PDT), wrote:


A simple voltmeter can give a lot of information particularly while
it's in 'failed' mode. While power devices (transistors and the main
audio power IC) can go 'thermal, I haven't seen a thermally sensitive
transistor in many years. The most common way back when was the TO-220
case devices - just like Q 701,702 and 705 but I would put money on
bad solder joints.

On the similar SA-160 which has 2 regulator transistors on the main
heat sink, all 6 terminals were cracked loose. After re-soldering
those I unsoldered the main power IC and resoldered it too since it is
mounted the same way as the transistors. Surprisingly, none of the
foil pads were damaged.

If you could render just a rough break-down of what was involved
in resoldering the 6 terminals, it would be very much appreciated.

Thx,
P

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."

"Puddin' Man" wrote in message
...
On Thu, 19 Aug 2010 19:51:55 -0700 (PDT), wrote:


A simple voltmeter can give a lot of information particularly while
it's in 'failed' mode. While power devices (transistors and the main
audio power IC) can go 'thermal, I haven't seen a thermally sensitive
transistor in many years. The most common way back when was the TO-220
case devices - just like Q 701,702 and 705 but I would put money on
bad solder joints.

On the similar SA-160 which has 2 regulator transistors on the main
heat sink, all 6 terminals were cracked loose. After re-soldering
those I unsoldered the main power IC and resoldered it too since it is
mounted the same way as the transistors. Surprisingly, none of the
foil pads were damaged.

If you could render just a rough break-down of what was involved
in resoldering the 6 terminals, it would be very much appreciated.

Thx,
P


Reworking cracked joints on a practical level involves no more than applying
a nice hot iron to the side of the joint, then when the existing solder
melts, running a small amount - no more than 2 or 3 mm - of new flux-cored
solder into the molten joint. Hold the iron on the joint for a further 1 to
2 seconds, then slide it quickly away. This should leave a nice shiny joint
(assuming this is standard leaded solder) with no signs of a crack,
dullness, or crystalline appearance. If you want to be really pedantic about
the job, you can remove the existing solder first, before making a new joint
with fresh solder, but in order to do that, you would need at the very least
some solder wick, and if you lack the soldering experience to be able to go
for this repair without checking on the best way to go about it first, I
guess that it's going to be unlikely that you have any, or the experience to
use it to clean the joint.

If you just go ahead and do it as I have described, you should be fine.

Good luck with it

Arfa

On Sat, 21 Aug 2010 02:49:17 +0100, "Arfa Daily" wrote:

Reworking cracked joints on a practical level involves no more than applying
a nice hot iron to the side of the joint, then when the existing solder
melts, running a small amount - no more than 2 or 3 mm - of new flux-cored
solder into the molten joint. Hold the iron on the joint for a further 1 to
2 seconds, then slide it quickly away. This should leave a nice shiny joint
(assuming this is standard leaded solder) with no signs of a crack,
dullness, or crystalline appearance. If you want to be really pedantic about
the job, you can remove the existing solder first, before making a new joint
with fresh solder, but in order to do that, you would need at the very least
some solder wick, and if you lack the soldering experience to be able to go
for this repair without checking on the best way to go about it first, I
guess that it's going to be unlikely that you have any, or the experience to
use it to clean the joint.

Much thanks, but I might've gotten ahead of myself a bit ...

I have 2 SA-R210's, both with problems. I put one in the shop about 10
years ago, they said they resoldered this and that, so I figgered
the problem with the other one would be cracked solder on components
attached to heat-sink, per suggestions in this thread.

I have it apart on a work-bench, and can look closely. When I carefully
probe solder points on components attached to heat-sink, I can't find
any obvious cracks. On the Q701, 702, 705 units, there is some funny
looking copper colored crud (flux?) around all solder points. The
Q705 E connector appears to be soldered-to (co-conductive with) one end of a
R704 resistor(?), but it's been that way for years. This is on a unit that I
bought on Ebay around 5 years ago.

If I have a "thermally intermittent power regulator" (plastic near-square
unit maybe 1" square, marked "Stereo Power Amp 3102 A"), I guess I'm out of
luck?

Anything else to look for? Other solder points on the bottom of the main
board look clean-as-a-whistle. Other components to examine/test??

Thanks,
P

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."

I brought the Technics SA-R210 receiver from US to Taiwan. How can I change the FREQUENCY STEP from FM/AM 200Khz/10Khz to 50Khz/9Khz to cure the problem of "No FM stereo" and "No AM"?
Thanks
Frank Yu

I brought the Technics SA-R210 receiver from US to Taiwan. How can I change the FREQUENCY STEP from FM/AM 200Khz/10Khz to 50Khz/9Khz to cure the
problem of "No FM stereo" and "No AM"?

It might not be possible without really major surgery... it looks as
if the SA-R210 may have been made specifically for the US and Canadian
markets.

The manual says that in manual-tuning mode, the FM can be stepped
along at a 100 kHz increment. It may be only the "auto-scan" tuning
which insists on stopping only on the odd 100 kHz frequencies.

On some Technics receivers of that era, pressing the "AM" button for
four seconds or more will toggle the tuner between 10kHz and 9 kHz
channels.

You could try a similar long-press on the FM button to see if there's
an undocumented frequency-offset change in the firmware.

On Tuesday, August 25, 2015 at 8:57:44 AM UTC-5, wrote:
I brought the Technics SA-R210 receiver from US to Taiwan. How can I change the FREQUENCY STEP from FM/AM 200Khz/10Khz to 50Khz/9Khz to cure the problem of "No FM stereo" and "No AM"?
Thanks
Frank Yu

You need skill. Here are the documents you need, if you have the skill to make the mods you have the skill to read the docs :

http://elektrotanya.com/technics_sa-.../download.html

Once there scroll down through the preview to some text, in that text you will find the word "processing". Watch that and when it changes to "Get manual in a minute or so, click it and download it like anytihng else. They just make you wait to be, well, you know.

That does not tellya, but it does tellme that it uses a certain chip for this, and the datasheeet will tell you :

http://pdf.datasheetarchive.com/data...DSA-434031.pdf

(they just lopped off a couple letter ans inserted "SVI" like they usually do)

If they don't allow a direct link it cam from here :

http://www.datasheetarchive.com/UPD1703-datasheet.html

there is like a spreadsheet of listings after the ads at the top, on the left there is a screenshot ot what looks like a datasheet front page. Under that are words. the last one is Download, that is the actual link.

I see there are pins going to the keybord that will nee to be set high or low logic levels. Good stuff gives you a switch, in this you might have to cut foil, and you will certainly have to install a jumper somewhere. No really, sometimes, rarely it is justy a matter of cutting something.

Same **** happens with shortwave radios sometimes. There are bands that are discouraged from being receivable in the US because SW braodcasts are supposed to ge intended for foreigh audiences. I remember the ****ed with American Dissident Voices of that. but the fat is the bands ADV broadcast on are not generally available on the regular SW receivers sold here. Apparently the FCC did not want us to hear what this country was putting out to the world. Go figure. This all goes back to why DVDs have REGIONS. We should be shooting them over that ****.

Anyway, the FM in the US has a high modulation, I believe it is +/- 75 KHz instead of +/- 50 KHz. It has to be a wider bandwitch for the same performance. We need like 200 KHz bandwidth for good performance, like down to like 0.4 % in stereo at full limiting. That is spretty good figure and you ain't going to get that here, you are not going to get rated performance with those IF filters, and the level WILL be too high because the detector is calibrated differently. Careful listening miugh reveal distortion due to that. there are two options if you want to be an audiophile about it but let's get htis done first ansd see how it sounds. It HAS enough bandwidth, and if you listen mostly to classical or jazz n ****, it might be just fine, and wirth a bit lower noise level. But at 100 % modulation, the thing is not going to meet its rated specs in THD.

Actually, I can fix that, but is it worth it ?

I just realized I read that wrong. Well if you are going to the narrower channel system things are a bit reversed. If they had ider IF bandwidth for here and you take it there, it is totally the opposite. You will have less THD but more noise. your FM output will be lower than it should be, but usually they do not want for gain so you might be just fine. If it really is too low, that can be taken care of as well.

Unfortunately, long-press on the AM/FM bouton will not work for this problem. The PLL IC could be SANYO LM 70XX, or Matsu****a AN7273, AN7470.... Let me find out later, then, see what I can do by modified the on board HW setting. I will try to down load the service manual again and again.... Thanks..

Thank you man! for those links that's for SA-210K model not mine SA-R210, a remote control model. I disassemble the unit, and found the internal circuit were totally different, such as SANYO LM7001 16pin PLL synthesizer working at 7.2MHz quartz crystal; MITSUBISHI M50720 408SP 42pin PDV display driver; SANYO LC6512A,LC6513A 4 bit uP controller.... There is no uPD 1703 as you found on SA-210K.

Now, the problem for me is how can I find a free down load of the service manuals for SA-R210? One for US and one for EU model to compare. Cause they sell the hard copy for 20 euro/dollar of each that I can nearly buy a vintage unit on the eBay.
Anyone has the idea to help, please...Frank