captainvideo462009@gmail.com: Jun 22 01:35PM -0700
This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny
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jurb6006@gmail.com: Jun 22 06:36PM -0700
I hope you mean a QRX, not QRS. They got it at hifiengine, it shows a fuse for the dial lamps, F 01, 5 amps. It also feeds a rectifier for about an 8 volt source that feeds the stereo light, also off the fuse. While at this age those lamps may have blown one at a time by now, you would have noticed it.
the cap in the protection, the failure mode is weird. They are usually 10 volts and sometimes go right across B to E of a transistor so they never charge more than like a half a volt. they get leakier and leakier over time. They are usually fed by a high value resistor, like 100K or more. I didn't look at that part of the circuit but since it is fine, fukit.
Not a badly designed piece. Full comp outputs, current source instead of a bootstrap, DC coupled. Theoretical peak RMS short tem power is 76.5 WPC. The rating is 30, so splitting the difference I would say you got about 1.5 dB or so dynamic headroom. It is probably over 3 dB for a couple milliseconds, but in real life not so much.
Tuner is pretty conventional, uses ceramic filters but still a standard ratio detector. No pilot cancel, but all that doesn't mean it doesn't sound good.
Tone controls OK, filters only 6 dB, don't use the filters. he variomatrix looks like a good thing, like Marantz varimatrix I would guess. You have control over the L+R attenuatoin in the rear.
I don't see amp strapping in it though, or pre out/main in.
Enough commentary, if it is QRX the manual is at hifiengine.com. It is probably ready for the FM to be tweaked, but it might not be so bad. Other than fixing the lights, if all the channels sound good I don't recommend anything. You could go in with an ESR meter and replace caps if you feel like it. Just never short the speaker wires because it has no current limiting at all.
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"David Farber" <farberbear.unspam@aol.com>: Jun 22 08:33PM -0700
> don't recommend anything. You could go in with an ESR meter and
> replace caps if you feel like it. Just never short the speaker wires
> because it has no current limiting at all.
Just a hunch here but I remember there were many Sansui models manufactured
in that era that had faulty rotary function selector switches. The result
was that the panel lights would flicker or go out completely. No amount of
switch cleaning would restore them to good health. If you wiggle the
function selector switch, do the lights flicker or does the meter function
momentarily?
--
David Farber
Los Osos, CA
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captainvideo462009@gmail.com: Jun 23 04:02AM -0700
> This is my own receiver. Last year it started taking longer and longer for the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were evident. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the protection board and .that resolved the protect relay problem. Now however there is another problem that I never had before. Most of the dial lights including the signal meter light are out and that meter also seems to be inoperative as well. I never had any trouble with any lighting or the signal meter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny
I think that I know what the problem is. I first sprayed the main
selector switch with a silicon based cleaner that contains a mild
lubricant, figuring that one of the phenolic wafer sections in the
.switch that was switching the power for the lamps perhaps was dirty.
This stuff evaporates quickly and it didn't solve the problem. After
more fruitless probing, in a last ditch effort I hit all the segments
of the switch with No Ox. This stuff is like "Blue Stuff" but a bit
more oily. I worked the switch to distribute the material and then
powered the unit on. No Ox works wonders with controls and switches
but it is some what messy.To my utter dismay I noticed smoke coming
off part of the selector switch. (This was probably from the sector
that is switching the high current lamp power. I now have to pull the
front panel and hope that I then will be able to get a better eyeball
of the selector switch. If the section is burned though I don't know
what I could possibly do though. A selector switch problem....... My
worst fear becomes a reality. Is today the thirteeth by any chance?
Lenny
On 6/22/18, Ardell Faul ardellfaul@gmail.com [tv-repair]
- Show quoted text -
Quick Reply
To: tv-repair@yahoogroups.com
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jurb6006@gmail.com: Jun 23 06:40AM -0700
Jump out the switch and see if it blows the 5 amp fuse.
I think 5 amps is a bit much for that type of switch.
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Cursitor Doom <curd@notformail.com>: Jun 22 08:14PM
https://www.diybanter.com/
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This message may be freely reproduced without limit or charge only via
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protocols constitutes acceptance of this condition.
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Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>: Jun 22 06:44PM -0400
On 06/22/18 16:14, Cursitor Doom wrote:
> https://www.diybanter.com/
Don't knock it. My sig block plus all the sci.electronics.design
scraping sites is a very effective SEO technique.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com
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N_Cook <diverse@tcp.co.uk>: Jun 23 07:33AM +0100
On 22/06/2018 21:14, Cursitor Doom wrote:
> https://www.diybanter.com/
At least you don't need f.c.ing javascript and the inordinate amount of
crap that comes with it , to view just a couple of kbytes of info.
Remember Google bought Deja-news and then proceeded to bastardise usenet.
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Allodoxaphobia <knock_yourself_out@example.net>: Jun 23 12:37PM
On Sat, 23 Jun 2018 07:33:39 +0100, N_Cook wrote:
> At least you don't need f.c.ing javascript and the inordinate amount of
> crap that comes with it , to view just a couple of kbytes of info.
> Remember Google bought Deja-news and then proceeded to bastardise usenet.
See my long-time usenet .sig
Jonesy
--
Marvin L Jones | Marvin | W3DHJ.net | linux
38.238N 104.547W | @ jonz.net | Jonesy | FreeBSD
* Killfiling google & XXXXbanter.com: jonz.net/ng.htm
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N_Cook <diverse@tcp.co.uk>: Jun 23 07:49AM +0100
Cheapo no-name/rebadgeable chinese video projector. Uses really only an
analogue IC to process baseband video and sound,
and mainly a TSUMV56RBUT-Z1 processor (LCD driver+ more) , only info in
chinese.
But mention of Android OS emerges in the otherwise chinese script.
So is it just a mobile phone LCD display in a box , changed firmware to
handle HDMI and SVGA inputs,rejigged pcb, plus high power LED floodlamp
instead of backlight, compound lens, mirror,2 fresnels , one pivoted for
keystone, and a radial fan for relative quietness, and a small speaker?
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bruce2bowser@gmail.com: Jun 23 02:18AM -0700
On Saturday, June 23, 2018 at 2:49:06 AM UTC-4, N_Cook wrote:
> handle HDMI and SVGA inputs,rejigged pcb, plus high power LED floodlamp
> instead of backlight, compound lens, mirror,2 fresnels , one pivoted for
> keystone, and a radial fan for relative quietness, and a small speaker?
Cicret Bracelet Phone?
-- https://www.youtube.com/watch?v=9J7GpVQCfms
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ggherold@gmail.com: Jun 22 10:15AM -0700
On Friday, June 22, 2018 at 10:28:46 AM UTC-4, Phil Hobbs wrote:
> > (I use a lot of BNC to dual banana plug adapters.. then I can watch
> > the fast stuff on the 'scope at the same time.)
> Ah. Those put a lot of torque on the solder joints, of course.
The solder joints look fine... OK I just retouched them... same deal,
(just as well cause I already spent $30 on the part Jeff linked to. :^)
When I replace it, I'll butcher the old one and see if I can find anything.
George H.
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Jeff Liebermann <jeffl@cruzio.com>: Jun 22 10:44AM -0700
>The solder joints look fine... OK I just retouched them... same deal,
>(just as well cause I already spent $30 on the part Jeff linked to. :^)
If the soldering is fine, then my best guess(tm) is that there's a
broken spot weld or press fit connection between the pin that goes
into the PCB, and the actual connection to the brass threads inside
the banana jack. If I'm right, the pin might fall out when you
unsolder it.
>When I replace it, I'll butcher the old one and see if I can find anything.
Umm... it's called an autopsy.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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"jfeng@my-deja.com" <jfeng@my-deja.com>: Jun 22 01:05PM -0700
> (I use a lot of BNC to dual banana plug adapters.. then I can watch
> the fast stuff on the 'scope at the same time.)
> GH
Banana jacks are so simple that, in the absence of obvious physical abuse, I find it hard to believe that it is intermittently faulty. I would try soldering test leads directly to the lugs; when that does not fix the problem, I would look somewhere downstream like a crack in a pc board or a cold solder joint.
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Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>: Jun 22 06:41PM -0400
On 06/22/18 11:50, Jeff Liebermann wrote:
> "Also, many old IFRs are having power supply problems. If anyone
> would like to do an article on troubleshooting and repair we'd
> be happy to put it here."
I power a lot of prototypes from random laptop bricks with eBay SMPSes
hung on them. The eBay units are generally quite okay as long as you
derate their output current by about 3X.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com
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Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>: Jun 22 06:48PM -0400
On 06/22/18 18:41, Phil Hobbs wrote:
> I power a lot of prototypes from random laptop bricks with eBay SMPSes
> hung on them. The eBay units are generally quite okay as long as you
> derate their output current by about 3X.
I should add that you can make negative supplies out of an eBay buck
regulator module by applying input power to +IN, grounding +OUT, and
taking the negative output between there and the original common ground.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com
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Phil Allison <pallison49@gmail.com>: Jun 22 04:47PM -0700
> I tried squeezing them in some, it's maybe a bit better, but no one
> wants even a bit of flaky in their test gear. Any ideas? (about how I might
> fix it.)
** You have tried using cleaning fluid ???
PCB cleaner or even WD40 will do.
An old handkerchief pushed home with a small drill bit is one way to introduce some fluid and clean the inside surfaces.
..... Phil
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ggherold@gmail.com: Jun 22 06:42PM -0700
On Friday, June 22, 2018 at 7:47:57 PM UTC-4, Phil Allison wrote:
> PCB cleaner or even WD40 will do.
> An old handkerchief pushed home with a small drill bit is one way to introduce some fluid and clean the inside surfaces.
> ..... Phil
No! I wiped 'em with IPA and a wooden cotton swab thing.
I'm away from the lab for a while so I won't be able to try
some other cleaner til I return.
George H.
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amdx <nojunk@knology.net>: Jun 22 09:22PM -0500
On 6/22/2018 10:05 AM, Tim R wrote:
> I agree with that but you're using a misleading singular.
> THAT.......is THE problem.......... falsely implies only one thing is wrong. I've been fooled a number of times because two things were bad simultaneously. Sometimes one caused the other but sometimes it's just random.
> In fact there is no theoretical limit to how many things can go wrong at once.
Oh, sounds like you worked on the first NAP VCR switching power
supplies! The parts dept finally came out with a repair kit, I think it
contained 8 parts, and it was strongly suggested you replace all parts
before applying power.
Mikek
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