Hitachi SuperScan Pro 800 - Schematic Wanted

[Toasty]

Hitachi SuperScan Pro 800
20" Color Monitor
Max resolution: 1600x1200, 60-75Hz
Model: CM800U

I'm looking for a REAL service manual schematic for this unit. By that I mean one that has signal levels and voltage levels marked on it, not just a block diagram. I have one from "off the web" and its okay for "basic" operations and setup, but not for tracking down a faulty component.

Their idea of repair is, if "A" voltage is good and "B" is not happening, replace mainboard. BLEAH! Sounds like a Zenith service guide from the 70's.

Not a board swapper then, nor now.

If anyone has or knows a source for this, the info would be most appreciated.

Toast

[Krankshaft]

Re: Hitachi SuperScan Pro 800 - Schematic Wanted

That was before my time but the TV repair books I read mentioned the "modular" TVs.

I bet the contacts on those boards caused more functionality problems then they fixed.

Did you try searching on a site like this?

https://www.manualsparadise.com

Is your model number CM800U??

If so they have your service manual with a schematic:

https://www.manualsparadise.com/Show...odel=M32282578

I've used these guys when I've been in a bind before their stuff is good.

[Toasty]

Re: Hitachi SuperScan Pro 800 - Schematic Wanted

>>I bet the contacts on those boards caused more functionality problems then they fixed.<<
Some did, some didn't. The connectors were mostly very durable. Most of the high powered stuff was jacked off of the chassis. The signal level stuff and low power such as audio were usually fine on the boards. In some sets the HO was off one of the plugins. On more than one occasion that led to some real nice fireworks.

The time saved in board swapping and the customer not losing the set for days while the chassis went to the shop, rather justified the whole scenario. But, so many "technicians" were nothing more than "board swappers". Ask them why or how it failed, and they didn't have a clue. "Did you scope it?" - blank stares were great!!!

I appreciate your positive feedback about the info on the manual site. I've seen quite a few of them and I am very leery of them for fear I'll spend The $15-$20 and end up with nothing more than what I already have. Their info is nil about what is actually contained within. It may have every schematic except the one I need. It'd be nice if they stated what schematics were in the file.

I'll continue working on the unit, but a schematic makes it easier to track down the problem.

[Toasty]

Re: Hitachi SuperScan Pro 800 - Schematic Wanted

Well, I kinda knew this would happen, but sometimes you've got to try...

I signed up and paid for the manual at manualsparadise.com. Took them 8 hours to get me the download link, which is okay, I guess. Their page does say it could take up to 24 hours.

Got the download link at 8:30 this morning and proceeded. Slow as molasses connection, I think dial-up was faster. Dropped to 8kbs and took a total of 15 minutes for a 3.6 Mb file. Usually thats <20 secs for me.

Got the file unzipped, it's a PDF, I see the size and say to myself "this is the same goddamn file I already have!".

Yup, same-same right down to the crooked and lopsided photocopies of several pages.

Blasted off an email to these ripoff artists and demanded a refund. They have until the next CC bill comes.

Manual is free at http://www.free-service-manuals.com/. If you join their forums, you can ask for 1 manual per week on the forums. Or, you can join their site for $5 a month and download all you can find.

That is where I obtained the manual from originally.

Lesson Learned: Stay clear of these sites and keep looking around. Eventually you'll find it elsewhere for either cheaper or free.

[Wizard]

Re: Hitachi SuperScan Pro 800 - Schematic Wanted

Ahh. Suspected that as I never went for that kind of crap pay me 'n download schematics.

What is the issues with this monitor, details, please?

Cheers, Wizard

[Toasty]

Patient Diagnosis

According to ex-owner, monitor had a picture shrinkage problem that had gone on for some time. It made a click sound and would pull in from the sides. I know the sound well because I have the identical monitor. It is a relay, and in mine I get the click sound and the same result, reduced horizontal sweep. It seems a tap on the case clears the problem so I'm certain it's a cold joint or loose connector somewhere. Okay, back to the victim...

While using the monitor one day, it suddenly went *pop* and went dark. Power indicator lamp stayed steady on. Cycle the power and it makes the degauss noise, but remains dark.

Okay, I inherit monitor and get it on the bench. Let me say this is a beast and it is a technicians nightmare. Five (5) shield panels must be removed to get to the chassis. There is a large 11" x 14" panel that holds a microprocessor board standing vertically and plugged into the mainboard at the rear. While connected, the only chance for access to the components is over the horizontal output section, straight down from the top or from the underside of the mainboard. The mainboard is completely outlined in a plastic guard/insulator that comes up past the edge of the board and extends into the solder side a full inch. There is no access to this area of the board without removal of this "guard". There is no moving the unit on the bench without assistance, as you have exposed components at the edge once the guard is removed. So here it sits, on its side.

Diagnosis so far -
- NOTHING accounts for the *pop* sound. No burnt smell, no burned, cracked, split, bulged parts, no arc marks, no scorching. It all looks like a brand new unit, sans dirt and expected discoloration for a 12 year old unit.
- the click sound is a relay near the yoke connection that jumpers a inductor on the board. Same sound mine makes and makes sense that it's something to do with the width control for different resolutions.
- no B+
- no High voltage
- B+ rises to 20-25 volts then shuts down and stays down until power cycle
- High voltage pulses to 2-3kv then off, follows B+
- unit has B+ switcher supply and a second separate supply for all other voltages
- other voltages seem normal
- Usual suspects (HOT) and surrounding power transistors all seem to test ok. Nothing shorted.
- traced B+ into horizontal section, lifting component legs as I went and watching B+ rise to nominal 50-60 volt level. I reconnect the component and move on.
- I'm now out near what appears to be the the horizontal section and can't seem to go any further.

HELP!

[Toasty]

Re: Hitachi SuperScan Pro 800 - Schematic Wanted

Update to downloaded manual. They (manualsparadise.com) have refunded my money.

"We regret to know that you were not satisfied with your purchase. We have just refunded your payment. We apologize for any inconvenience this may have caused to you, and hope you will visit us again soon."

[Toasty]

Re: Hitachi SuperScan Pro 800 - Schematic Wanted

To improve the exposure of this topic, I've created a new one which addresses the problem versus looking for a manual. Hopefully to elicit the help of more members.

Click here to go to new topic.