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sx650 parts (need a relay)

blhagstrom

blhagstrom

Mad Scientist, fixer.
Subscriber
Hi guys,
New member here. Been lurking and reading along. I have an sx650 that has gone south on me. I'm fairly sure it is the protection relay. (I've tried everything else I found here and finally started to probe the unit after I got a schematic). I have full voltage going through the relay coil but no "click". The new ones are almost $50. Since this is just "another" one of my receivers and I'm not 100% sure of my electronics skill, I have to put that much money into it. Anyone have have a junker that I can scam a relay from cheap?

Blaine
 
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Digikey says mid-January. Mouser is another month back from that. There are other sources, but it seems they all have a minimum order ($35, or 10+ devices).

Sit back and wait, I guess. You can place the order with Digikey, and it'll ship as soon as it shows up.
 
You can order a 653-MY4-DC24 from Mouser, it has solder tabs that have a hole in the center of the tab, that can be clipped through the hole at 12 O'clock and either 9 O'clock or 3 O'clock to narrow the pins.

Choose 9 or 3 depending upon if there is room to the right or left because the pins will put the relay about 1/16" offset from centered.

Or you could go crazy (NOT recommended) and turn the holes in the pcb into slots that will accept the tabs. THAT takes a VERY steady hand, lots of practice and a PCB drill and bit combination.

You could burnish the old relay's contacts and wait for stock to arrive, too.....
 
Not a burning issue

Thanks for the info.
This isn't a burning issue (but 2-3 months is a long time). If I lose patience, I'll think about the "close" one and tab trimming.

I did burnish the contacts but the problem is that the relay is not engaging.

The history is, it worked fine for quite a while. I moved it and suddenly it started to cut out. On for a short while, then out. Sometimes in and out a few times. I've tried to find a learn from all the threads here and finally came to the "diagnosis" that something was keeping the relay from firing up. Since I have full voltage across the relay coil (34v if memory serves) and it turns on and off right, and it has continuity, I've decided it is a bad relay. A shorted relay coil seems reasonable. Movement (of the whole unit and the boards during partial disaaembly to get at things) probably helped complete the short until it now will not click in at all.

Since it worked fine while clicked in, I assumed the rest of things are OK (or at least OK enough).

I found the LONG thread about trouble shooting and fixing the $10 sx-650 that was a bad resistor. Perhaps I could learn much from that and follow along and do some more testing while I wait for a relay to be available at a reasonable cost.

I've always loved these old units and I've had friends that were electronics hobby people (up to the point they got real schooling and became experts). I have an interest and some brains but never had time to hobby at it. I can fix just about anything else in the world (that can be fixed) so this is a chance to see if I can learn up enough to fix simple things. I think I know what I shouldn't do or try. Over the years I've picked up enough tricks and tips and tools to probably be slightly handy.
 
FYI, these relays seldom fail. I've replaced hundreds because of worn-out contacts, but in all the years of fooling with them, I have seen perhaps one with an open coil.

The DC level on the output pins of the SP-40W output modules need to be checked (pin 4). If one or both of the modules are bad, the relay will refuse to close. Pin 1 should read about +36V, and pin 5 should read about -36V.
 
OK, you are already taking voltage readings, so let me point out which ones and where for the best effect...

BUT your description of "moving it" inducing the problems opens another avenue of inquiry - bad solder joints, probably in the power supply section. They run hot and the expansion and contraction can crack thin ones over time. Check all joints by trying to move each joint's component lead with a sharp probe, on all the power supply's power transistors (larger 1/2 inch square ones) two marked "d313" and one marked "b507", or just re solder them preemptively. They could also have a grainy or crystallized appearance.

Then if that doesn't git er goin, read these voltages to 3 digits(42.5, 1.24 etc...) and post them:

On the power amp assembly awH-060, read the voltages on (bare metal chassis ground referenced) the board's pins 12, 14, 28 & 29

Read the two modules pins 1, 2, 3, 4, 5, 6 & 7.

They will tell us if the amps are behaving.

On the gwR-101 board, read the AC voltage on pin 31. That is connected to the lighting circuit, and is used to tell when the receiver is turned on and off.
 
voltage readings

Hmmm, I don't have a AWH-060. Do you mean GWR-101 Power Amplifier Assembly 2?

Readings from the #2 assembly (the one with the power ICs)
pin = reading
12 = 36.3
14 = 33.6
28 = 36.3
29 = 33.6

Modules (power ICs, right?)
pin = reading
1 = 34.6
2 = 0.0
3 = 34.6
4 = 0.0
5 = 34.8
6 = 0.0
7 = 34.7

GWR-101
pin = reading
31 = 7.5 AC

After re-assembly to get it stable for power readings, it has now started to click in and out. Sometimes on for up to a minute or so. I found an old "fixed-it" thread about someone fixing the indicator lights and it helped the relay and it was stated that there was a connection between the lights and the relay power up. I had one bulb acting up and so I replaced it with a 7.5v .22a (closest I happen to have). Did that make enough difference to get the relay to start "trying"?

From the threads, I already saw the ones about checking solder joints and I've gone over both amp boards 2-4 times. I did pre-empt resolder the three large transistors.

I mentioned "moved" since that is when this all started. It worked fine at home for a while (some months with occasional use). I took it to work (swapped it for a Sansui a friend helped me fix at that job, we liked the music on so...) Anyway, once on site at work, it started the relay issue. I have an SX-680 with a good amp and dead tuner, so I took that and ran them in pair to make music. Changed jobs a few times and now I found an interest in trying to figure this out. My "electronic" friends are all distant now.

Except you guys. Thanks for all the help!

So, do the readings tell us anything?

Blaine
 
We're getting there, you didn't post the polarity of the voltages.

Plus there are two modules... we need readings from both

And the pins 3,4 & 7 readings need to be represented down to 0.001 volts, as each 0.001 volt on those pins are significant.

You need to watch the pin 4 voltages while the relay is cutting in and out, and see if there is a pattern.... basically if those two voltages stay below 0.6v (0.1 really) there is no justification for the protection clicking in.

You may need to replace two capacitors and two transistors in the protection circuit. It isn't as likely because the sx-650 DOES include a relay "flyback" protection diode for the relay driver transistor.

But something does look fishy with those readings on the modules.

Insulate all but the very tip of your probe, so when you slip (we all do) you won't short two pins together.
 
Stupd button off

OPPs,

I had the stupid button on, that's why the readings are weird.
I took readings off the board pins 1,2,3...7

FROM Power IC pins 1...7
Pin side1 side2
1 +35.2 +35.2
2 +1.275 +1.292
3 +.045 +.054
4 +.022 +.031
5 -35.1 -35.1
6 -1.220 -1.221
7 -.001 +.008

Now the darn things has clicked in and running so I can't get a pattern off the
click in and out. (Did probing help a contact? The solder joints on the IC are
really heavy and look OK. Cracked board trace? Weird.)

I powered it up and down a dozen times and its working fine. I'll try again later to see if I can get a in-out pattern, if it does it again.
 
Still sounds like an intermittent / cracked solder joint.

You could do the few parts in the protection circuit that are known to be vulnerable.

Obviously, those module voltages are correct.
 
Do the few?

Thanks, it does act like a bad joint somewhere but I just don't see anything.
I could re-solder everything on the boards.

Is that basically what your saying for "do the few that are known to be..."?
Re-solder them? Which ones specifically are you speaking of?

Dang thing has been running about 99.9% all day now. When I started this thread it wouldn't run at all.

There has to be something that gets "flexed" when I move the boards to get at things.....

The very small readings on pin 7 are no big deal?
 
markthefixer said:
<snip>

BUT your description of "moving it" inducing the problems opens another avenue of inquiry - bad solder joints, probably in the power supply section. They run hot and the expansion and contraction can crack thin ones over time. Check all joints by trying to move each joint's component lead with a sharp probe, on all the power supply's power transistors (larger 1/2 inch square ones) two marked "d313" and one marked "b507", or just re solder them preemptively. They could also have a grainy or crystallized appearance.

<snip>
Click to expand...
I do that all the time - quicker sometimes for tracking an intermittent fault.

First inspect, if no luck, resolder. I have a power iron with pump that makes quick work of it - BUT be careful of polystyrene caps - stay AWAY from those joints. Those caps have a silvery plastic semi-clear construction and are extremely heat sensitive.
 
yup

OK, Thanks,
I had already checked and resoldered those transitors and anything else that looked like it might be cracked (and I have excellent near sight). I thought there was some others that I hadn't pickup on in the threads.

I even found a wire wrap on the main power input that wasn't finished from the factory (can't believe it worked all these years). After that, I checked all the wire connections.

The joints on the boards all look thick and strong, but there must be one hiding. I've gone over it 3-4 times and given up just as many times until I thought I had it cornered in the relay winding. That's when I started the thread. Now that seems wrong, unless the coil is shorted and moving it cuts the short (I really don't believe that one). It does seem odd that I can have power through the relay coil and it doesn't activate, unless its just old and has some leaking and can only "just" engage.

And now it's working so well its hard to probe for missing voltage. When it does cut out, it only stays out for a second or two.

I'm going to move it back to the bench and go over the joints again.

I just love intermmitent faults. I work in software and do mechanics and sometimes it takes months to years to find an intermmitent fault. (I found a bad factory battery cable on an '87 Lincoln in '02 that had been driving the owner nuts. There was just enough connection to work, when it wanted to and it was hiding inside the terminal cover.)
 
You should do at least the 2 protect caps and two transistors, preferably 6 caps.

Then the protect circuit is trustworthy. This usually clears a lot of strange intermittents as the transistors and caps have aged. The replacements are also far more robust.

C21, c22 0.22uf 10v
598-DSF050J224 0.22 50

C26, C27 330uf 6v
647-UPW1A331MPD 330 10

C33 3.3uf 10v
647-UPW1H3R3MDD 3.3 50

C36 220uf 16v
647-UPW1V221MPD 220 35

Q14 2sc1647 ecb
512-KSD1616ALBU to-92 ecb x60v 1a 0.75w 160mhz 135-400hfe $0.09
edit 2/7/2010 this transistor is ok here

Q15 2sc1384 ecb
512-KSC2690AYS to-126 ecb 120/a160 1.2a 20w 155mhz 35-320hfe $0.40
 
Last edited:
markthefixer said:
You should do at least the 2 protect caps and two transistors, preferably 6 caps.

Then the protect circuit is trustworthy. This usually clears a lot of strange intermittents as the transistors and caps have aged. The replacements are also far more robust.

C21, c22 0.22uf 10v
598-DSF050J224 0.22 50

C26, C27 330uf 6v
647-UPW1A331MPD 330 10

C33 3.3uf 10v
647-UPW1H3R3MDD 3.3 50

C36 220uf 16v
647-UPW1V221MPD 220 35

Q14 2sc1647 ecb
512-KSD1616ALBU to-92 ecb 160v 1a 0.75w 160mhz 135-400hfe $0.09

Q15 2sc1384 ecb
512-KSC2690AYS to-126 ecb 120/a160 1.2a 20w 155mhz 35-320hfe $0.40
Click to expand...

Parts arrived and replaced. Still getting an intermmitent cut out.
Do you have any pointers on where to go, what to do next?
 
Now we start watching the power supply voltages and the amplifier output voltages. There will be a SIGNIFICANT difference in one of them between the normal state when the speakers are energized, and when the unit is in protect.

We can be reasonably sure that the protect circuit isn't the problem, but rather responding to an input.

Pins B & F are the amplifier output monitoring terminals, and should be around 0 volts, 0.1v is becoming a problem and by 0.6v the protect circuit should have triggered.

Pin H should be -34v (regulated) or so
Pin P should be +33v (regulated) or so

These would have to practically disappear to have an effect
Pin 1 on each module should be about +36v unregulated
Pin 5 on each module should be about -36v unregulated

You have to catch it in the act, start by watching the two amplifier outputs, then the regulated power supplies, finally the unregulated supplies.

A fault in one of the power supply can cause the amplifiers to go out of whack, so don't stop measuring if you see one or both of the amps rise above or below zero volts.

The power supply monitoring isn't specific enough to pinpoint if one amp isn't getting the REGULATED supply voltages, (bad connection to one of them) but the measuring of the module's pins will catch any faults with the unregulated supplies. In that case, only one of the amp channels will be misbehaving.
 
good and bad

Well its been running most of the time but has started to act up enough again to get reading.

B is running around 0.02V relay in and out
F is running around 0.03V relay in and out

H is running around -36V relay in and out
P is running around 33V relay in and out

1 and 5 on one module run 34.8V and -34.8V relay in and out
1 and 5 on the other run 34.8V and -34.8V relay in and out

These seem close enough, so good news? Bad news, I'm no closer to finding the problem?

More hints please.
 
I don't want to interject where I shouldn't, but it occurs that possibly a wire under the insulation could be broken. Had a hall effect pickup do that once. It had solid wire instead of stranded like original part did. The wire broke halfway down the length of the wire under the insulation and would work fine most of the time. Just a thought.
Regards. Ron.
 
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