Question for Merrylander

archie2

Addicted Member
A while back you gave an ID and source for larger heat sinks to replace the ones pictured for the CR 2020. I could not find it in a search. Can you repeat it please?
 

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Simplest thing then would be to go to mouser online and check their catalog. Heatsinks are in the tools and power section. Do realize that if you put in anything larger be sure to use the mica insulators as there currently is a large voltage difference across the two sinks. Also, Radio shack uses to carry a nice 3/4" square heatsink with about five fins sticking out the back.
 
Would this work? width: 19mm, height: 9.5mm, length: 19mm or 0.75" x 0.37" x 0.75"
 

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Mica insulators where the sink contacts the board or where the resistor contacts the sink at the screw? I bought the last RS ones in my locale and put them in my Sansui 8080DB.

The pictures I've seen of this mod show a single heat sink connecting the two STK chips. I can understand why insulation is needed in that case. Why would you need two of those? Or am I missing something?
 
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Decided to leave well enough alone. The receiver runs cool, it's been running for 3 hours and the transformer and center heat sinks are barely warm. The STK chips are hot but not so hot as they significantly heat the immediate area. I'm not going to touch them but holding my hand 1/2 inch above them is midly warm.
 
When you say STK you confuse me, the two transistors you show in the picture should be 2SD525 or TIP41C if the mods have been done or 2SD234 if not.
 
When you say STK you confuse me, the two transistors you show in the picture should be 2SD525 or TIP41C if the mods have been done or 2SD234 if not.

My faulty knowledge. I thought they were regulators but I saw STK chip in the other thread mentioned in this one so I called them that even though they didn't look to me like STK chips. Nor did the mods done in the other thread look like they were in the same area as my picture. The mods have not been done in my CR 2020. I believe I was looking for heat sink TO 220 or TO 202.
 
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What was the reason the service bulletins for the mod changing the two TO-220 was issued?
 
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What was the reason the service bulletins for the mod changing the two TO-220 was issued?

As I understood, overheating. They were cooking off their own solder joints or baking surrounding components. There's also the Main PS caps and replacing all the fusistors with flameproof resistors. The SB also includes the addition of a jumper wire across some AC line terminals in the rear, IIRC tying the 2 sides of the power switch together to reduce arcing internal to the switch.

I've also done the mods on CR-1020, although it doesn't need upgrades for the TO-220's on the PS sub asm board. Rob has been a great mentor for the n00bs like myself on stuff like this. Props to EW and Avionic as well. AK is full of knowledgeable and helpful members.
 
The bulletins are on the AK Yamaha database and if anyone does the mods to a 1020 please note that the 2 watt resistors are 10 ohms as opposed to 33 ohms on the 2020.
 
As I understood, overheating. They were cooking off their own solder joints or baking surrounding components. There's also the Main PS caps and replacing all the fusistors with flameproof resistors. The SB also includes the addition of a jumper wire across some AC line terminals in the rear, IIRC tying the 2 sides of the power switch together to reduce arcing internal to the switch.

I've also done the mods on CR-1020, although it doesn't need upgrades for the TO-220's on the PS sub asm board. Rob has been a great mentor for the n00bs like myself on stuff like this. Props to EW and Avionic as well. AK is full of knowledgeable and helpful members.[/QUOTE

Thought it might be the heat. I'm badly short of space and toying with the idea of placing an Altec 345A tubed amplifier on top of the CR 2020 using four or five 2 inch sections of small pipe foam insulation as spacers. I also would have a 12V fan running off a 5V transformer cooling the CR 2020. Right now I'm testing a cheapo fan. The trick is to insulate the fan from grill contact as much as possible for noise reduction.
 

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Thought it might be the heat. I'm badly short of space and toying with the idea of placing an Altec 345A tubed amplifier on top of the CR 2020 using four or five 2 inch sections of small pipe foam insulation as spacers. I also would have a 12V fan running off a 5V transformer cooling the CR 2020. Right now I'm testing a cheapo fan. The trick is to insulate the fan from grill contact as much as possible for noise reduction.

I would be somewhat weary of a fan, But only because of the potential for dragging in dust and causing problems. I don't know the layout of the amp, though...so it may be ok as is. Even if its not a dusty enviroment, dust still winds up where fans are (ex. computers). But for noise effects, i'd actually run below voltage (unless it is a naturally quiet fan), or put in a potentiometer or rheostat to regulate yourself.

also: for heatsinks, sometimes places like Bgmicro and AllElcectronics (and various other small, odd parts dealers) have good heatsinks for cheap. especially for small-scale to-220 and the likes.
 
I would be somewhat weary of a fan, But only because of the potential for dragging in dust and causing problems. I don't know the layout of the amp, though...so it may be ok as is. Even if its not a dusty enviroment, dust still winds up where fans are (ex. computers). But for noise effects, i'd actually run below voltage (unless it is a naturally quiet fan), or put in a potentiometer or rheostat to regulate yourself.

also: for heatsinks, sometimes places like Bgmicro and AllElcectronics (and various other small, odd parts dealers) have good heatsinks for cheap. especially for small-scale to-220 and the likes.

Dust is a consideration, I'm trying out various filters on the fan. The fan is a 12V and I have it running off a potentiometer. If/when I put the Altec on top it will not extend to that part of the grill directly over the hot regulators. there will be 4 inches of unobstructed grill on that side. Thanks for the heatsink places, I will check them out.
 
Simplest thing then would be to go to mouser online and check their catalog. Heatsinks are in the tools and power section. Do realize that if you put in anything larger be sure to use the mica insulators as there currently is a large voltage difference across the two sinks. Also, Radio shack uses to carry a nice 3/4" square heatsink with about five fins sticking out the back.

I found one of the finned Radio Shack TO-220 heat sinks and the mica insulation. Does the mounting screw need to be insulated both front and back? Answer to my own question is no. . It looks like a tight fit.
 
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The bulletins are on the AK Yamaha database and if anyone does the mods to a 1020 please note that the 2 watt resistors are 10 ohms as opposed to 33 ohms on the 2020.

Found and printed. If I can reduce the heat via the Radio Shack TO-220 heat sinks I'd rather go that route as I am very much a novice when it comes to modifying SS gear. I don't want to practice on a CR 2020.
 
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