HH Scott 370R question

jkcoondog3

jkcoondog3

Active Member
I have had this HH scott for several years. I am not the original owner. Question is when I turn on receiver lights flicker for sometime, but does eventually turn on. Is this an issue? Do I have a relay problem? Any help will be appreciated.
 
Register to hide this ad
Probably a dirty power switch if it's flickering at start up for a few seconds.
 
Yep, sounds like the super common weak power switch issue found on many, many receivers of this vintage. For years I always installed small "ice cube" relays to take the load off of the weak switch contacts, but anymore I do the simple Triac mod as described in this thread here : http://www.audiokarma.org/forums/index.php?posts/10170892/

Had nothing but success with this mod, used it in everything from a 15 wpc Realistic to a 100 wpc Kenwood and everything in between. Make sure to clean up the switch contacts as best as you can first, then it should be plenty good enough to trigger the Triac / Thyristor device which in turn does all the "heavy lifting".
 
My Scott 370 had a Shite power switch too. I swapped it out with a residential light switch, and it worked great after that. There are more elegant solutions, but I was 14 at the time and the internet didnt exist yet, really.
 
sparklow said:
This is a relatively easy fix. My Scott 350R suffered from the same problem. It is burnt contact points in the power selector switch. See this thread for the cure.
http://audiokarma.org/forums/index.php?threads/pioneer-sx-450-power-switch.700078/
Click to expand...

@sparklow - did you make this fix? Would you be able to post a picture of how this looks after the fix on a scott 3x0R? i have a nice 380R that i would like to do this fix on to head off the eventual power switch issues.
thx.
 
Greyrat said:
i have a nice 380R that i would like to do this fix on to head off the eventual power switch issues
Click to expand...
g'day; are your lights flickering? No? I would leave be and save the pdf. and look at @audiojones post#4 as an option.
However if Yes?
In the event that 'sparklow' doesn't respond. (3yr. old thread) the pdf provided a pretty good description of what to do once you accessed the switch.
 
no my lights are not flickering on the 380r. I had a 370r previously that had flicker and sizzling sound from the power switch. I sold that unit. I was actually looking to do the @audiojones triac mod - just wondering if anyone has done it on a Scott of this era and had any pics or notes. Thx for replying to this oldie thread.
 
Actually that brilliant Triac mod isn’t my idea, all the credit goes to @K7sparky. His thread (linked in my post from a few years ago above) has very good detailed instructions. Any time I run across a receiver with this type of power switch it’s the first thing I do, I don’t wait for it to start arcing and sizzling. Just did a Lafayette LR-2200 recently even though it was working fine, it’s just a matter of time with those cheap switches that are on the back of the speaker selector.
 
I had a kenwood kr-4070 rcvr with the same problem. There is a good write up on this on how to fix. It was a pretty easy fix for me. Something about using the unused contacts of the switch. Do a search on it and it will turn up.
 
I have resolved this with a brand new switch on a Scott 390R. I had to 3D print some small bracket to accommodate it to offset the screw holes.

Let me see if I can find the pictures. If not I can open it up and get some.
 
I did the Triac mod on a slightly older Scott R75s. I used Q6040J7TP which is overkill ratings wise, has solder eyes on leads, and an insulated tab. I mounted it to the inside of the chassis near the power switch. There was enough slack in the wiring so that it was very easy. Works flawlessly. My switch was fine, but I was doubling the filter caps and wanted to avoid stressing the power switch (although that just made it the same as the R77s which uses mostly the same parts).

Good luck
 
Well I could not find many pictures so I opened it up...

The switch can be ordered from Mouser, you need two..

The first picture is the old switch, you can see the little metal bracket that holds it in place. There are actually two switches in a sandwich configuration, one had been removed already.
You need to replace the old bracket with a new one. You can trace the old one and cut it out on some sheet metal or plastic or 3D print it. I will see if I can find the file....

Also the new switches are a bit thinner than the old ones so I needed to use a few washers.

44512125741_d94cd1a51b_b.jpg



This is the new pair of switches installed.
49679762642_d7309234ca_b.jpg



49679762582_8416de17bf_b.jpg
 
You must log in or register to reply here.
Back
Top Bottom