View Full Version : Zenith System 3 - jumpy picture with some game consoles


RetroHacker
08-08-2017, 07:55 PM
My daily watcher is a Zenith System 3 console (model SM 2535X7). I have it hooked up to several different devices, and it works with pretty much everything (VHS, Beta, LaserDisc, DVD, etc), but I've found that some game consoles - such as the PlayStation or the Super Nintendo - will produce an unstable, jumpy picture. Other games, like the original NES, Gamecube, and most other things - seem to work just fine.

I've done a bit of reading, and found mention of problems with the Playstation and certain Zenith sets. Something to do with the countdown IC for H and V drive not being able to cope with the signal from the game. Is there any fix for this? Any modification I can perform that'll let my set work with more video sources? I need to overhaul the set anyway and replace a few capacitors, so I might as well try to solve this issue while I'm in there.

-Ian

zeno
08-09-2017, 05:19 PM
Long time ago but I THINK there was a jumper you could move
on the 9-152-? module. BUT I may be thinking of another brand.
Also try the RF AGC control on the 9-151 board. And the norm-spcl
aft switch AND the TV-CATV-HRC switch on front panel.
There probably a Tech Topics on it but I thew them all out yrs ago:nono:
Maybe someone else remembers.

73 Zeno:smoke:
LFOD !

old_tv_nut
08-09-2017, 07:20 PM
I recall an IC being redesigned at some point to handle the games problem. I do not recall if there was a version with a jumper, but it's possible.

RetroHacker
08-09-2017, 10:38 PM
I already tried every possible setting for the front panel controls, to no avail. I guess I'll just have to wait until I'm inside to hunt for a jumper and mess with the AGC control. If anyone does find any docs on this subject, I'd love to hear what you find, however! It's interesting that this was apparently a very real problem with these sets, and yet you rarely hear about it. I know Sony had a modification to the Playstation to correct this problem - but as I have found, the Super Nintendo does it too. And this set would have only been about 10 years old when the SNES came out, and there were probably a lot still in use. I wonder how many disappointed kids there were on Christmas morning as they found their brand new Super Nintendo doesn't work on the family TV.

The crazy thing is that the old original Nintendo works fine. As does the Atari. I've even had an Apple II connected to this - well known for it's off-spec video signal. And even that worked fine. But the Super Nintendo, Playstation, and the Philips CD-I don't work.

-Ian

NowhereMan 1966
08-19-2017, 11:14 PM
I noticed that with my PS1 on the 1982 Zenith System 3 but the PS2 runs fine. I'm glad someone else had noticed this too.

Findm-Keepm
08-23-2017, 12:31 PM
From Sam Goldwasser's FAQ:

14.15) Bouncing picture on some (Zenith) TVs

The problem of a shaking picture on some TVs (notably, Zenith models) is due
to a problem in the PlayStation sync generation, not really a TV failure.

(From: Jerry Jessop (jjessop1@home.com)).

PlayStations will sometimes slowly "bounce" on older Zenith chassis sets,
this is due to the way the vertical sync is outputted on the PlayStation.

Call the PlayStation 'hotline' and explain the problem, it is well known and
the system will be modified at no charge to you and you will get a free game
for your trouble!

A small daughter board will be installed that will correct the problem.


I doubt Sony will do this some 20 years later....

Electronic M
08-23-2017, 01:52 PM
PS1 games play on the PS2 and the PS2 is fine with Zeniths. The simplest solution might be to just upgrade to a PS2 and use that to run your PS1 games.

lnx64
08-23-2017, 03:10 PM
PS1 games play on the PS2 and the PS2 is fine with Zeniths. The simplest solution might be to just upgrade to a PS2 and use that to run your PS1 games.

How true is that though? Because when it plays PS1 games, it doesn't output 480i like the PS1 does (on most games). It'll run with the same video modes as the PS1 itself, and usually I've seen that while PS2 games work fine on the older Zeniths, the PS1 games on a PS2 would also have issues.

Has to do with how they handled that weird 240p "hack" of the video signal.

RetroHacker
08-25-2017, 07:03 AM
And, it's not just PS1. The Super Nintendo - which I'd be wanting to use more anyway - doesn't work with the Zenith either. The Philips CD-i also doesn't work, but no loss there....

Ideally though, I'd have a fix on the TV side of things so I could use anything without worry.

-Ian

pomponij
09-11-2017, 11:23 AM
I had this problem in 1992 playing my SNES on my 1979 Sylvania Superset. After tinkering for weeks to no avail I called Nintendo's 800 number for assistance. They said that a modification to the SNES was available at no charge at any authorized Nintendo service center (Norman's Electonics in the Atlanta area was the only one around) I never had the modification performed and I still regret it. I wonder if anyone still has the literature for the modification.