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Question about the Mitsubishi U70 Hi-Fi SVHS
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mjl1297



Joined: 17 Jun 2006
Posts: 22

PostPosted: Sat Jun 17, 2006 6:23 am    Post subject: Question about the Mitsubishi U70 Hi-Fi SVHS Reply with quote

I'm new to the forum and have a question regarding the VCR above. When I load a tape it plays for a moment and then shuts down. Removing the top I see that the forward reel is not rotating. I've been to several websites and they say a Q574 is at fault. Unfortunately, none of them bother to tell me what that is. I guess it's sort of like the person who needs no introduction at a party so no one tells you their name. Shocked This VCR has sat dormant for years. The reason for that brings me to my second question. When I put it up it would no longer play my SVHS tapes. I could hear the sound but the image was scrambled. Any idea what may be at fault here? I'm not willing to invest much in this machine's repair but if it's a matter of a few dollars and a bit of time I don't have a problem with that. Of course, I still have the receipts on what I originally paid for this thing and I could just weep! Crying or Very sad
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vtech



Joined: 08 May 2006
Posts: 1264
Location: USA

PostPosted: Sat Jun 17, 2006 10:16 am    Post subject: Reply with quote

Sure do remember the expensive HSU70 &very familiar with---repaired many. As a matter of fact still have two that i hardly ever use.

More than likely you have a mechanical problem. First thing is the capstan belt (underneath) which will eventually turn into mush & won't grip ....Could also be the pinch roller/ idler or even the mode select switch but check the belt first

SVHS problem can be a leaky capacitor on hybrid board.--but it has to play regular tapes first.
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PostPosted: Sat Jun 17, 2006 10:43 am    Post subject: Reply with quote

It will play regular tapes without incident. I'll check the other stuff though
.
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mjl1297



Joined: 17 Jun 2006
Posts: 22

PostPosted: Sat Jun 17, 2006 10:44 am    Post subject: Reply with quote

Anonymous wrote:
It will play regular tapes without incident. I'll check the other stuff though
.


Oops, that's me up there!
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vtech



Joined: 08 May 2006
Posts: 1264
Location: USA

PostPosted: Sat Jun 17, 2006 12:24 pm    Post subject: Reply with quote

Wait a sec..perhaps i misunderstood you, thought you mentioned take-up reel was not rotating with a tape inside? Are you saying take-up is not working only with SVHS??---if so it's strictly coincidence

The tape transport is not gonna know the difference between VHS or SVHS tape as far as take-up or any mechanical operation is concerned.
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PostPosted: Sun Jun 18, 2006 12:41 pm    Post subject: Reply with quote

No you understood the question correctly.
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mjl1297



Joined: 17 Jun 2006
Posts: 22

PostPosted: Sun Jun 18, 2006 12:43 pm    Post subject: Reply with quote

Anonymous wrote:
No you understood the question correctly.


back when it would play tapes there was no problem viewing regular VHS.
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mjl1297



Joined: 17 Jun 2006
Posts: 22

PostPosted: Sun Jun 18, 2006 2:11 pm    Post subject: Reply with quote

Capstan/idler belt DEFINITELY needs replacing. Any more thoughts on the scrambled video during the playback of SVHS tapes? What capacitor might it be and where would I get a part to replace it...inexpensively?
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vtech



Joined: 08 May 2006
Posts: 1264
Location: USA

PostPosted: Sun Jun 18, 2006 11:07 pm    Post subject: Reply with quote

K, as far as SVHS goes, while it is a rather complex path & can be caused by variety of capacitors, the NUMBER ONE problem was associated with one of the hybrid IC's on the SVHS circuit. It is actually a 8 or 8 pin thin in-line IC that is mounted on the SVHS pc board--usually siliconed next to adjacent part by the famous white mitsubishi silicon compound( if i remember correctly it is on the sandwiched board)'

The following actually involves the parts mounted on the IC itself (unless you are familiar with this-- do not attempt)

The SMD cap mounted on the IC itself will eventually leak out & sometimes make a mess on the surface of the IC. Of course the easiset way would be to replace the entire Ic which has long been discontinued.

I've had to repair many of these ic's [repairing etched traces(if any) & replacing the offending SMD cap on that ic] which will restore SVSH picture.
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mjl1297



Joined: 17 Jun 2006
Posts: 22

PostPosted: Sun Jun 25, 2006 9:07 am    Post subject: Reply with quote

Is that chip still available and is it worth my while to even attempt the repair or should I just try selling this on Ebay for parts and buy a new SVHS from a vendor?
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