rebuilding an OG ms1000 Nickel

[ttocs]

I was not sure what I was going to do with the heatsink I got on here mainly because of money and also because I wanted an amp I could use and not feel bad about. The nickel seemed a little more of a show/admire piece then one to put to use so I considered trading for a TA version. After a little thought though I realized this would be my only chance to own a nickel more then likely and these were built to be used no matter how good they look.

So after that I started a search for the guts to fill that thing with and it took longer then I thought it would to find someone to part with one. I was hoping to find an OG/green torriod maybe with heat sink damage so I would not feel bad taking apart a good amp but the only two I came across were both in mint shape. You can't make an omelette with out breaking a few eggs. They started off their lives rockin as a 2250 but they have earned the upgrade is how I look at it now. its freezing in the garage so I decided to start this project as it will take some time to make/source a couple of the parts. I need some help with a few things if anone knows where to look:
1.) I need to find a nickel plater that is not industrial size, or that will do small batch projects. I have talked to 2 places so far and when they find out I only need the end plates done, they don't respond anymore.... I would not mind them keeping them till they had a full batch, it doesn't have to be done tomorrow. If anyone knows of one please let me know I would love to get them off and leave them time to do what they need, maybe hold them to fit in another batch, what ever...
2.) Gold screws - anyone know the pitch thread needed for the transistor press-bars? Anyone know where to get gold plated screws?

I also need to make the transistor pressbars but I have an local anodizer I have worked with that I am hoping will not have a problem making them the purdy purdy blue they need to be.

I started off today by taking the first one out of its shroud to give it a good cleaning. There was a thin layer of crud that came off with IPA and a lint-free cloth using the eraser of a pencil to get in the small areas. It shined up nicely although I have to wonder if anyone ever gave the power bars a light trip down a buffing wheel? Is the plating to soft with a super soft flannel wheel and and a light compound?

[trickyricky]

The transistor clamp/pressure screws are 4-40, don't know where to get gold plated. Second I wouldn't mess with the gold buss bars because they are not cloudy...they have a plastic film over them to protect them from accidental shorts. If you want them to shine just remove the plastic protective film but you run a risk of shorting them out when handling it.

[ttocs]

the net is a beautifull thing. Thanks for the screw size any idea on length? A quick search led to this.

http://usaknifemaker.com/screw-4-40-soc ... -20ct.html

Does the 1000/2250 use silpads or paste? Looks to be a mix of both from what I can see.

[vwdude]

I believe it uses very thin anodized metal sheets, at least the TA does. if you plan to use the clamp bars you will need a foam tape of sorts since the different transistors are different thicknesses and will need equal pressure on them. that foam tape is attached to the back of the clamps themselves. then on the other side, you will need to insulate the metal backed transistors from the bare metal heat sink. thermal paste isnt enough, so outside of the above mentioned anodized metal plates, id just use thermal pads. maybe use some thermal paste as well.

if you want part numbers for thermal pads, thermal paste, and even spare pre-driver heat sinks, check out the secret parts page on the registry. to access it, along the top youll see a 'parts' section. just below that, click on (or just above) the purple line. itll take you to a page I compiled of useful replacement parts for PG amps.

[ttocs]

very cool thanks man I will check that out.

I had a thought last night and curios what people think about getting the press bars franked instead of the usual blue? Its different but not a radical change and yet still in the pg relm while custom so I kinda like it but not sure....

[RayBuck]

Why frank them nickel them

[ttocs]

Nickel? interesting.... very very interesting.... I would say I like the contrast of the blue/purple to the gold screws holding them but gold/nickel is an intersting contrast with a bling factor. Not normally my thing but interesting... Of course it still begs the question of where lol?

[RayBuck]

True on the where I have no idea. Don't get me wrong I like the frank look but it may look tacky in the 1000. Who knows. ..keep after it man

[ttocs]

after some thought and looking at pics I think the nickel idea on the pushbars would almost make them blend in. With the bright anodized blue pg picked its a nice contrast from the nickel sink and then matches some of the wiring details as well. The franked color would be close but idunno. Tried another plating place today but they don't do it either... I thought nickel was the first coat needed to chrome most stuff and didn't think it would be this hard?

[trickyricky]

Am not an expert on metal finishes but do know that there are powder coat finish that can resemble chrome (mirror finish, will be twice as expensive as a regular off the shelf color). As for nickle plated transistor heat sink clamps, it doesn't matter if they are anodize, powder coated or nickle plated that will cause them to bend or distort. It's the material you are using and the thickness that will be the blame for any distortion or bend to the bars. I would use 3/16" or 1/4 thick flat stock aluminium that is 3/4 to 7/8 wide. You can buy a 3ft piece for around 10-15, then you can figure out which one you are going with (anodize, powder coat chrome, nickle plating).

[ttocs]

David temple was just taking a 1000 apart today on facebook so I had him throw a ruler on his and get the exact measurements of the clamp bars and the screws.

[vwdude]

Scott do you mean me? I'm David Werner.

[ttocs]

oh yea, close enough for me

[ttocs]

Scott do you mean me? I'm David Werner.

today I find the material I need and then can't find that pic with the measurements in it. How long were the press-bars again? I am not worried about the holes as I will match that up to mine to be sure but after looking back through 2 months of pics I can't find it.

[ttocs]

I believe it uses very thin anodized metal sheets, at least the TA does. if you plan to use the clamp bars you will need a foam tape of sorts since the different transistors are different thicknesses and will need equal pressure on them. that foam tape is attached to the back of the clamps themselves. then on the other side, you will need to insulate the metal backed transistors from the bare metal heat sink. thermal paste isnt enough, so outside of the above mentioned anodized metal plates, id just use thermal pads. maybe use some thermal paste as well.

if you want part numbers for thermal pads, thermal paste, and even spare pre-driver heat sinks, check out the secret parts page on the registry. to access it, along the top youll see a 'parts' section. just below that, click on (or just above) the purple line. itll take you to a page I compiled of useful replacement parts for PG amps.

I finally got around to getting the pads/paste. When I go to the parts section I see plexi, I see wire terminals but not sil pads nor paste unless I am missing it?

[ttocs]

anyone have any help on the paste/pads?

[Jacampb2]

They did not use sil pads. They used hard anodized aluminum insulators. I have never seen anything remotely similar available retail. I assume that they were produced for PG directly. The isolation plates in their ZX/ZPA/ZxTi/Ti amps are a similar principal. I have gotten the distinct impression that you have to be very sure of your anodizer. These things have excellent thermal conductivity, but rely on a micron thin layer of what is essentially sapphire. It is not widely used in industry because any little oops in the anodization and you have power devices directly shorted to the heat sink.

If I recall correctly the Sapphire amps also used the anodized insulators. I have sanded smooth and kapton taped damaged ones before. Sapphires are normaly somewhat reasonable, maybe could gather some ot part out for insulators. Other than that you could go ceramic, they are widely available and also have good thermal characteristics. You could also use thin aluminum and kapton tape, but at that point you may as well just tape the heat sink and not worry about additional insulators unless you need the devices to sit a certain distance from the sink.

What do you mean by "paste"? Thermal compound? Are you looking for the same as PG used, or just a good recommendation? I don't know what PG used, but Dow Corning 340 is very good thermal transfer compound. If you end up using sil pads, you are not supposed to use thermal transfer compound. It destroys the properties of the sil pads.

Good Luck,
Jason

[ttocs]

thin anodized insulators... Well now things got interesting. Yes my local guy has been good but I am not even sure what ask about here. What would he be anodizing? Not sure what the best available option is but I would really love to get this thing back together and running again in tip top condition. Any suggestions on what could be used is greatly appreciated. I had an idea where to get the silpads but now with all this I have no idea where to look or even what to call them.

Yes by paste I meant the compound. I have another part of the car that needs it as well so I was hoping to kill 2 birds with one stone. Thanks for the recomendation I will see if that last electronics supply store in town is still open and has it.

[trickyricky]

Jacampb2 is correct, the nickel plated has anodized aluminium thin insulators (thermal compound on underneath side and then between the device and anodized aluminium insulator). The Sapphire series use similar thermal insulators but I don't believe they can be used as they are different size and have holes in the wrong dimensions compare to the nickel ms1000.

I think it may be wiser just to go with the silpads, like the 2125/2500/2250 but if you can get the insulator anodized and cut then go that direction.


Here's a sapphire, you'll see the black anodized aluminium insulator sandwiched between the devices and heat sink.

[Jacampb2]

Normal anodizing is not sufficient for use as a dielectric. You have to have whats called "hard anodizing" or "hardcoat anodizing" or "dielectric anodizing". If you google any of those terms you will start to see some data on the subject, but even so it is not a very common thing to do. There is no way I would take a chance on a business that has never done it before unless they are knowledgeable on the subject and have the equipment to test the dielectric strength of their oxide layer. Also, the stock insulators are very very thin, my off the cuff guess is like 24 gauge aluminum or thinner.

Ceramic may be a good option if you do not want to have the (IMO uglyish) Sil-pads. I know you can get ceramic insulators from Mouser and Digikey, I have not really investigated much as to what sizes and configurations are widely available.

Good Luck,
Jason

[ttocs]

I know my anodizer has the ability to do hardcoat and to test thickness as he did it on one of the pieces I had him do. I made a methanol tank out of aluminum and had to ensure the inside was hard coated to prevent it from corroding. Is it just a really thin piece of aluminum he anodizes? I do have a metal supplier in town that might be able to help but as you said it might be better to look into the ceramic. Will they just show up in a search for ceramic insulator on digikey/mouser or is there another technical name for them?

[Jacampb2]

Here you go, these are in stock at mouser, Clicky. I seem to remember them having more options, but I am not seeing it now. I may have run across them somewhere else, I will look some more... I did just find that the same company that makes the linked ceramic insulators also makes a hard anodized aluminum insulator. They don't stock them though and minimum order is 5000 at $1.72 each...

I'll keep looking, I know I found a bunch of ceramic insulators somewhere...

*edit* here are a few more options from digikey: Clicky

[ttocs]

thanks a million dude.

[trickyricky]

4180G Ceramic are a great choice and only 30 cents more than the silpads....

[RayBuck]

Why can't you use the ones that were in the 2250? Or am i missing something.