Sony SLV-780 Resurrecting The Beast

[John-Del]

On Monday, February 26, 2018 at 1:33:58 PM UTC-5, jurb...@gmail.com wrote:

"You were lucky. I'm still throwing out all sorts of worthless electronic parts from VCR days. "

I have seen motor drive ICs go bad, after all they are a power output. End and reel sensors as well. Never a microprocessor. I suspect something in the system control circuit, but the IC last, after all other relevant things are checked.

I can no longer recall the brands they were used in (Akai?), but NEC uPcs in VCRs were problematic. We stocked them. IIRC, the numbers on them had the prefix uPc.

 

>"I thought you said you had one just like it? "

I have, I think a 720 which uses the same mech and chipset. With the lack of information it is a learning tool, iused it to figure out a few things, like using only the record prevent switch and end sensors for the front loading mech. Nifty way they didit actually. Saved components and cost but still works. Wellit did.

"Not hardly. I have a 5000 sq ft shop full of "Shit with wires."
Only the truly deserving get a one way trip to the dumpster. "

My yard was 3,500 sq ft. It wasn't all that nice and I abused it. The junk I had would have overloaded the dumpster for years. I had a junk room that got so full the (wood) floor broke through. What did I do ? I put more junk in it. the building wasn't long for this world anyway.

But I do not deem high end VCRs worthy of a trip to the dump. Some people still like them, use them, and others fix them.

What I need is a beta rewinder. I shit you not. I have an SLHFR60 and HFP100 hifi adapter and ;lots of old tapes, some of them camcorder tapes with memories on them. Same with the VHS.

More on it in my reply to Terry.

 

>"Don't you find watching old tapes on a modern TV painful? "

I find new shows and movies much worse. They switch the video so much so fast that you can't see anything. Flashing on the screen - ifit was red and blue you would think you sre getting stopped by the cops. Thoroughly annoying, as if some little kid is working the board. Not to mention effects that almost make you think your TV is malfunctioning. And they can't seem to get the picture size and aspect ratio right on some channels. Plus there is no creativity anymore. Simply unwatchable.

>"I've gone down that route, and the picture quality stinks, even with very good equipment. Unless the screen is small, and even then..... "

The picture quality was fine for most of my life. On my projo KPR36XBR the display from the Sony SLV920HF had the smallest test I ever saw on a standard NTSC TV. On that set it was sharp and clear. I had aligned the COMB filter to perfection. The convergence was perfect. It was actually better than a direct view. Even though the screen pitch of the lenticular wasn't that fine, each section reproduced all colors in the exact same space, a color CRT can't do that. In the stores they had these things right next to the direct views and they looked as good except for the vertical viewing angle. The horizontal viewing angle was about 170 degrees or something like that. The small text was broken up on a direct view, my projo reproduced it perfectly, and that is without even an SVHS (Y/C) input.

The Sony VHS video performance is superb, for standard HQ VHS it is only surpassed by beta. Of course later formats were better, higher frequency video carriers on the tape, less white clipping and compression, and a few other things. With only SVHS it only went through COMB filter instead of 3. Now that I am more used to the Y/C input I am even more sensitive to a poor COMB filter.

But the quality is actually fine. I don't even have an HDTV anyway, and don't really want one. I can't see much difference unless it is very large screen anyway. My sister has an HDTV in the upstairs apartment, I can always watch that but I don't see enough difference to make it worth it. Maybe she does because she has better eyesight.

I remember fixing VCRs, I did alot of them. On soem I had to call the customer and give them the bad news that fixing theirs would cost almost what a new one would be. Some of them OKed the job, why ?

For one they finally learned to work the timer. Those were the days when you could use that, now you have to rent a DVR to effectively record or you are stuck to one channel until you physically go and change it. That would have been nice when there were good programs on. Now it is hard to find anything worth watching. Back then though sometimes there were multiple things on at the same time. With multiple VCRs and raw cable you could do it, and not worry about losing everything in a crash. You had the physical tape out of the machine.

It wore out, sometimes the machine would damage them, they had their drawbacks, but for what I want they fit. I also have a turntable that plays 78s. A Dual 1216, a decent quality one. I bet you would have to go at least a mile to find another one who can play a 78. And I can transfer it to the PC and burn it to a CD. I don't really play 78s, but I do play some vinyl once in a while. And on audio forums (fora ?) there are people who have $ 10,000 turntables, soem even more. It does have a certain quality to it, though that might not be so objective. However there is onre thing, the frequency response does not drop like a rock right at 20 KHz, it rolls off smoothly. Some people may be able to hear the difference. In fact I was reading that some people can actually see light wavelengths that others can't. Into the UV or IR or whatever. They might be the people with superior night vision. My buddy is like that. We were walking out in the stix and he had no problem, I was practically blind.

My ex-boss could see the numbers on planes in flight. Later though he needed reading glasses. He was a licensed pilot, something I would have loved to do but I was born with bad eyes. I was about to join the air force like my Father and Uncle but found out that I was not likely to ever fly because I needed glasses.

Last but not least, most of what I watch was originally recorded in standard NTSC. There is no way to get back the lost quality of that system. There is only one system worse in the world, the old one they used in the USSR. Every other country in the world either has NTSC, and many have something better. Well had, with digital that is all out the window.

Everything I own is over 10 years old except my PCs and printer, and they are getting close. And I like it.

 

>"I can no longer recall the brands they were used in (Akai?), but NEC uPcs in VCRs were problematic. We stocked them. IIRC, the numbers on them had the prefix uPc."

Some Sonys IIRC as well. A few others but not every model. There were also TA (Toshiba), LA (Sanyo) and a couple others.

They were all power products and subject to failure. Sometimes the PC was discolored near them due to heat. Also STKs in the earlier non-switching power supplies, changed a bunch of those. I don't know if those are Sanken or Sanyo.

One bad micro I saw was in an RPTV, a Hitachi. A proprietary part. I ran it down to the shutdown input that came from the HV and current detectors. The whole chip was alright except for the pulldown resistor for that pin. A simple 10K resistor fixed that.

With jungle I+CS it was about 50/50. I avoided changing them until everything else was checked and it was usually a cap or high value resistor.

I was the one who fixed things the other techs couldn't and sometimes I got them with the jungle already changed. I could change them with zero damage usually, even the fine pin ones, as long as they were through hole. I got them half butcherd with ;lifted pads and they were jumpered in, so I had to check that before even beginning to actually troubleshoot.

Then one day it was mentioned that I used more solder wick than the other techs, I replied "Yeah, and I've seen their work". You are not normally supposed to be able to tell a repair has been done. Add to that the fact that they needlessly changed a bunch of ICs because they were not good troubleshooters. Usually when I called it the chip, it was the chip. The others seemed to guess. That's why I got the big bucks. Now I am practically unemployable. But I do what I can, it just takes longer.

 

[Fox's Mercantile]

On 2/27/18 8:45 PM, jurb6006@gmail.com wrote:

I also have a turntable that plays 78s. A Dual 1216, a
decent quality one. I bet you would have to go at least
a mile to find another one who can play a 78.

Easy enough, I got a Technics SL-2000 all it took was a
simple change to the direct drive feed back. Instant 78
RPM, then a Shure M78 cartridge.



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

 

[Fox's Mercantile]

On 2/27/18 8:59 PM, jurb6006@gmail.com wrote:

You are not normally supposed to be able to tell a repair
has been done.

The only way you can tell I've been "in" something
is the date code on the part is newer.


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

 

On Tuesday, February 27, 2018 at 10:21:04 PM UTC-5, Fox's Mercantile wrote:

On 2/27/18 8:45 PM, jurb wrote:
I also have a turntable that plays 78s. A Dual 1216, a
decent quality one. I bet you would have to go at least
a mile to find another one who can play a 78.

Easy enough, I got a Technics SL-2000 all it took was a
simple change to the direct drive feed back. Instant 78
RPM, then a Shure M78 cartridge.



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

Of course your average Joe can't do that. I looked at the print and it doesn't look like it's quartz locked. But then that is not required. Looks like a resistor change and you were in business.

With cartridges like that I like to get another headshell. It is much easier to change. Also, I see it uses the screwing in and out counterweight method of applying stylus pressure. That means you can weight the headshell to get the proper 78 tracking force, which I believe is higher. The anti skate probably isn't calibrated for this anyway, and it might not even need adjusting. I assume you wired it for mono right there to nip some of those ticks and pops in the bud.

I can't really weight the headshell in the Dual because the tonearm is totally statically balanced and the stylus pressure is applied by a calibrated spring. Sure I could do it but lose that balance. Probably not a big thing but it is cool that when setup properly it will play up on its side. It would play upside down except for minor details, like the record falling off. And I have seen alot of them without the E ring or whatever holds the platter on.

What you did, it will wear out the motor faster, but not bad. It will probably have to work a bit harder but only during startup.

Pretty cool anyway, still not many people can play 78s.

Have you heard about them picking up the material on 78s optically with a LASER ? When I read about that I thought it would be a waste.

 

"The only way you can tell I've been "in" something
is the date code on the part is newer. "

Yup, I clean the PC board. I try to get the same amount of solder on all the pins of an IC. At Electrasound they had us clean the board with Qdope thinner which is toluene. I usually use acetone. And I do it after desoldering and before soldering. The flux won't be burnt so it is not conductive and provides just a wee bit of insulation.

One thing I do my way regardless of hoe the manufacturer did it is that I apply the heat sink compound in a daub or bead and when mounted and tightened let the pressure squeeze it out. This prevents air pockets which could occur if you spread it out first. Apparently it is cheaper for the manufacturers in some cases to spread it out, and you can tell it was done by a machine, because if anyone, they should know this.

There are a few other things I do that enhance reliability here and there. Or did actually. At Electrasound which was authorized for just about anything, even GM car computers and radios, they said "Do you want to take their name off of it and put yours on ?".

In some cases - yes. If I have to fix it if it breaks again I will do whatever I deem necessary to prevent that callback. The customer will blame me no matter how bad of a piece of shit they built.

And you can't tell them shit. Like different problems. I fix a convergence problem then it has a totally different problem and it is my fault. I try, "If I put brakes on your car and the radiator goes, do I have to change that for free ?". Falls on deaf ears. Ignorant ears actually. Like if i fix the right channel in an map and the left channel goes, that's me ? Bullshit.

Stupid people wrecked that business. They told me a long time ago that you get enough money out of them the first time to cover such things. I didn't like that but over the years I learned that's the only way to really keep good customer relations. Just fix the damn thing.

And then when it comes to the complaint, "It was working fine and just went out". You get it alive and find out it has a weak CRT, convergence issues, noisy digital board, needs caps all over the place with retrace lines. Working fine eh ?

I am glad to be out of it. I argued with the boss, a customer was tired of waiting, we had ordered parts. Under Ohio law there are some strict guideline about estimates, but still, once the customer OKs the estimate that is a contract. So I said "OK, tell them to pay the bill and they can have it unfixed". Hey, we ordered expensive parts for that thing and now they are going to sit on the shelf ? I would even let them come and pick up the parts when they come in. But they CAN'T take it to a bunch of shops that might be hacks and expect the estimate to hold. So it is back to that. If nothing happened the price is still good, if something happened then we'll see.

I was sick of getting fucked up the ass without lube.

One time we lost a TV. (not my shop, I worked there) It was not economically fixable so it wasn't worth much but they sued for $ 800. The thing MIGHT be worth that in like new condition. Well we found the set. They said OK and the boss and them agreed to just forget about court. So he didn't go, but this prick did and got a default judgement.

Towards the end of my days owning a shop I got to the point where I would not work on anything I hadn't sold. That did not cause me to get out of business, I got partners because we had the space and wanted to go into appliances. These kids wee not old enough. Quite frankly neither was I. If I knew then what I know now I would have never let them into the business. Maybe hire them and they could work for me, but that is it. No more partners ever again.

Enough of my rambling. I seem to have hijacked my own thread. LOL

 

[John-Del]

On Wednesday, February 28, 2018 at 2:49:29 AM UTC-5, jurb...@gmail.com wrote:

"The only way you can tell I've been "in" something
is the date code on the part is newer. "

Yup, I clean the PC board. I try to get the same amount of solder on all the pins of an IC. At Electrasound they had us clean the board with Qdope thinner which is toluene. I usually use acetone. And I do it after desoldering and before soldering. The flux won't be burnt so it is not conductive and provides just a wee bit of insulation.

I used to buy a lot of Flux-Off when it first came out, then other non-freon based cleaners as they were introduced to clean any pc solder work (looks nice and it may turn up an unintentional adjacently soldered land). Nowadays I use acetone and a fiber brush. Much cheaper.


> One thing I do my way regardless of hoe the manufacturer did it is that I apply the heat sink compound in a daub or bead and when mounted and tightened let the pressure squeeze it out. This prevents air pockets which could occur if you spread it out first.

On transistors and small ICs, I put a dot on the die area and just screw it (or the heatsink) down. But I've found on very large ICs (like the STK convergence outputs), there is no way to tighten the mounting screws tight enough to squeeze most of the compound out. On large flat ICs, I carefully put a very thin schmear on the IC and tightened it just snug. After soldering the pins, I'd give it another quarter turn as the compound relaxed. After test running a couple of hours, I'd give it a last torque when hot to squeeze the rest out.

 

>"But I've found on very large ICs..."

On STK type ICs if they screw down I run a bead between the screw holes. If they clamp down I put the bead in the middle across most of it and squeeze the shit out of it until it starts oozing out of the edges. At that point I am careful not to lift it off the heatsink. Sliding it around helps sometimes if it is large and you heatsink compound is thick, but not so far that it can introduce air in there.

And shit is the word, we used to call it bird shit.

It also makes a good insulator for CRT anode caps, and it never dries. You can usually get it wet and it won't arc if you use it. On projo TVs they are usually siliconed to the glass and need to be replaced once you take them off.