1987 Sharp TV Model 13MM57

[jmm83]

I bought this sharp 13inch tv today the guy dropped it off. it's from 1987 it even has the remote but it's missing the tinted plastic piece that goes over the led channel display does anybody have one. or know where i can get on made for it.

[TVTim]

Great find! Amazing picture on it.

[compucat]

You might be able to buy some tinted acrylic sheet and cut out the piece you need. I imagine the required thickness to be only a few millimeters. You could likely find it online or at a craft shop. Finding an original part is almost imposible short of acquiring a parts set.

[zeno]

Good strong looking set. The red lens was probably part of the front
cabinet. In the day you couldnt buy the lens but had to order the
whole front cabinet. Compucat sums up the alternitives.

73 Zeno
LFOD !

[Popester]

Wow that chassis has no dirt. Was this ever used. Jug puts out a very nice picture.

[centralradio]

Nice set.The color of the tomatoes are right on the money.Love the 13 inch sets since they dont take up much room...

[jmm83]

the cover for the front looks like this
https://lauraslastditch.zibbet.com/1...vintage-13mm57

[zenith2134]

These sets use a Toshiba Blackstripe CRT. I attribute that fact to their great picture quality.I have got a few, an '83, '84, and an '87 and all worked as found with a killer picture. The chassis themselves are basic singleboard design, nothing to write home about, but some of the most reliable I've seen.
My 13" Sharp from '84 saw heavy use over the years and finally developed a collapsed vertical. Fearing I'd have to source the IC, I simply touched up the pin solder and it has been rock solid since.

[centralradio]

Sharp was promoting the "Linytron" name back in the 1980's.I have a couple in the kitchen in line to be looked at.One is the same digital tuner set that jmm83 posted here and the other is a regular 2 knob channel selector style set .The model number tag is gone on the digital set so if its the same as the 13MM57 is a good question.My late friends shop with the same name as my users name in honor of him as a great friend and mentor was a dealer and repair these sets there..

.

RIP Joe as I lost him about 2 years ago at 99....

His main lines were Zenith. Sylvania and RCA ...

Hope the CRT is crisp as yours 13MM57 Jmm83..

[LittleOldTV]

I recently picked up one of these and it seems to have some extremely strong artificial sharpening. Either that or there's some other problem creating the typical halo artifacts you see with a high Sharpness setting. Unfortunately there's no Sharpness knob and I can't find a schematic for this CRT anywhere, not even on the paid sites. I looked over the whole board and didn't see any potentiometers except the R / G / B ones on the neck board.

Anyone know if there might be a way to disable the Sharpness or turn it down? Even if it involves something like scratching off a trace. I really like the picture but the Sharpness artifacts make it awful for gaming:

[old_tv_nut]

If you had a schematic, it might be possible to identify video peaking components to modify.

BUT, this image shows pre-shoots, which can come from two places:
1) luma delay line and asociated components - maybe changeable, maybe not
2) IF response design - not easily changeable

[LittleOldTV]

Originally Posted by old_tv_nut

If you had a schematic, it might be possible to identify video peaking components to modify.

BUT, this image shows pre-shoots, which can come from two places:
1) luma delay line and asociated components - maybe changeable, maybe not
2) IF response design - not easily changeable

Thanks for the response. What does IF refer to? I've never heard the term "pre-shoots" before. Is that what the white artifacts along the left side of the 'S' in Super are called? To me it looks exactly like what happens when you crank up the Sharpness on any other CRT. I don't know much about '80s CRTs but I know many had artificial sharpening so that's what I assumed it was. I was surprised this one doesn't have a Sharpness knob -- maybe there's no sharpening after all.

I guess I'll try requesting a schematic from SAMS but I'm not very hopeful they'll find anything.

[old_tv_nut]

IF refers to the intermediate frequency amplifier stages.

The usual sharpening in the video amplifier section creates a following opposite polarity pulse, that is, to the right of the edge being sharpened; so, a black object gets a white outline on the right side, called an "overshoot." If a circuit can affect the phase as well as the amplitude of the frequency response, like the IF amplifier can, it can produce a leading white transient before a black object, called a preshoot. The typical sharpness control adjusted the frequency response in the video amplifier and therefore changed only the overshoot intensity. Set designers made the IF to produce a fixed desired preshoot to match the middle setting of the customer sharpness control overshoot. It's was a matter of taste to decide what this "middle" amount of sharpness is, and it was baked into the design. Some very late models of analog TVs (like the last Zeniths) had integrated analog video circuits that could control the amount of both preshoot and overshoot simultaneously, which was much more like a studio monitor.