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Sansui 4900Z Flickers and flutters and is dim when first turned on?

Ric Harris

Ric Harris

Active Member
Picked up 4900Z at goodwill last week for 20 bucks:banana: I walked into goodwill and from about 50 feet away I saw it and knew by it's look it was something good. I rushed over saw Sansui picked it up and walked right to the checkout giggling the whole way.100_1186.JPG 100_1188.JPG 100_1192.JPG 100_1196.JPG
When I first turn it on the displays are dim and flicker like it's starved for power or something. It lasts for 10-15 seconds and then it comes to life and works awesome for hours on end,
It's got good power that comes through very clean. The tuner is stupid as it's that 80's transition to LED displays. Very attractive unit anyway. I can't complain at 20.00.
Nevertheless what makes it struggle so to get going? Power supply? Oxidized fuses? Any guesses?
 
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Have you cleaned the switches and controls yet? Could be something as simple as the power switch arcing and trying to establish good connection.
 
The power switch tends to wear out on them... I found a replacement that worked good for a 5900z at Mouser...
 
The tuners are quirky until you get to the 7900Z.

Nice find though. And I agree, power switch.

Rob
 
bberkom said:
Have you cleaned the switches and controls yet? Could be something as simple as the power switch arcing and trying to establish good connection.
Click to expand...
Haven't cracked it open yet. I need to pick up some mass airflow sensor cleaner first. That's what I use for cleaning electronics. Will give the pots and buttons a thorough bath.
 
The Fuxtor said:
The power switch tends to wear out on them... I found a replacement that worked good for a 5900z at Mouser...
Click to expand...
I found a couple switches on Ebay and they want as much as I paid for the receiver and there's no guaranty they work. I'll try cleaning it first.
 
Likely you're gonna need to take that switch apart and burnish the contact points back to bright metal. That xxxxZ series of Sansui performs very well.
 
macyjrm said:
Likely you're gonna need to take that switch apart and burnish the contact points back to bright metal. That xxxxZ series of Sansui performs very well.
Click to expand...
I am assuming soldering will be required in this little foray. I solder poorly. However I can when called upon.
 
AC power switches on receivers and amplifiers don't generally respond well to contact cleaner because the resulting oxidation caused by arcing contacts does NOT clean up well with spray.
Adding to the fact that arcing generates heat that also weakens switch contact pressure, adding to the arcing problem.
I have fixed switches that aren't too damaged by disassembling the switch, cleaning the contacts and re-tensioning the contacts.

Mark T.
 
Ric Harris said:
I found a couple switches on Ebay and they want as much as I paid for the receiver and there's no guaranty they work. I'll try cleaning it first.
Click to expand...

Why would you want a used switch already half way or more to the point of needing the service your current switch needs? When you get inside or if The Fuxtor can help out find a good new switch at one of the new parts suppliers.
 
MY reasons for fixing the switch are-

A) It may be "more work", but the pleasure of accomplishing the repair suits me just fine and I learn a new skill(s). :thumbsup:

B) My father taught me "use it up, wear it out, make it do". (We impressed each other with our "skills", he showed me how to adjust a carburettor and I showed him how to align an old radio, he sold cars, I did electronics, things "balanced out", when I had a wage "slump", he got a raise, when he "slumped", I got a raise). :bowdown:

C) Fuxtor paid $12 for the part and had to wait for it, I fixed the switch, learned from it, persevered the original part, and had $12 "extra" for dinner at a favorite restaurant (I did things differently, Fuxtor did what he "saw fit" and it worked for him, no arguments or criticism here). :beerchug:

D) This world is too "disposable", when something breaks, just "toss it" (Why do you think we HAVE "collectible" equipment to "play" with in the first place?)" :idea:

End of my "small rant" IMHO! :D

Mark T. :music:
 
You might look at the way the switch is wired.

A lot of them use DPDT switches but only use one pair of contacts. You may find the "other side' of the switch intact enough to be usable. I'd still put a triac on it to protect the "good" side of the switch.
 
Hak Foo said:
You might look at the way the switch is wired.

A lot of them use DPDT switches but only use one pair of contacts. You may find the "other side' of the switch intact enough to be usable. I'd still put a triac on it to protect the "good" side of the switch.
Click to expand...
I believe that is also a very good thought!
 
markn2wae said:
AC power switches on receivers and amplifiers don't generally respond well to contact cleaner because the resulting oxidation caused by arcing contacts does NOT clean up well with spray.
Adding to the fact that arcing generates heat that also weakens switch contact pressure, adding to the arcing problem.
I have fixed switches that aren't too damaged by disassembling the switch, cleaning the contacts and re-tensioning the contacts.

Mark T.
Click to expand...
Yeah I usually use that stuff on pots that are scratchy or rca plugs. One thing I can say about Mass Airflow Sensor cleaner is flashes off fast and not nearly as caustic as some contact cleaners. It really does work great on pots.
 
So the next question is my primary music receiver is a Magnavox 1500. The Magnavox is the superior piece of equipment. (For those not familiar, it was produced pre Phillips buyout at the same Fort Wayne plant that produced Apeg musical equipment. It's a serious but quirky piece)
Here's the scoop the Magnavox is getting needy and I'm tempted to sell it in favor of this Sansui. Decisions decisions.
Any thoughts?
 
Superior is superior.... enough said? Never heard the Magnavox before but I think the Sansui's always sound good!!
 
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