Looking for a 450V to 500V adjustable power supply for tubes

[Alan0354]

hmm no heatsink compound on that plate, I don't know about this quality.

It was never screwed in. What can you do. You just buy and use it. I sure not going to design and build one.

 

[soundmotor]

The unit I purchased for charging caps (forming) on rescued pieces before testing.
https://www.ebay.com/itm/EC125-E-125-Digital-power-supply-cell-gel-electrophoresis-/152771889481?_trksid=p2047675.l2557&ssPageName=STRK:MEBIDX:IT&nma=true&si=lFmFgqa%2FkiSpOsl%2FQ9Nuj4bnODk%3D&orig_cvip=true&rt=nc

That's pretty sweet. I've wondered about those things since one came in a search. Never really looked at what they do before now.

 

[whoaru99]

Actually it looks like it would be simple to replace much more so than a return

I agree. It doesn't look like it would be exceptionally difficult.

 

[maxhifi]

If you get a hex head screw with the same thread, it would be easy to install it with a small wrench. Then you don't need to take anything apart.

If you can't get a hex head screw just get a long screw and cut it down to a stud, then thread a nut on it and tighten that with the wrench

 

[whoaru99]

I would even first try using the appropriate screwdriver bit held 90-degree style using a small wrench or needle nose Vise Grip.

 

[s-petersen]

That's pretty sweet. I've wondered about those things since one came in a search. Never really looked at what they do before now.

It's pretty heavy, and has a brute of a transformer in it.If I can bypass the need to have a load(part of the safety system)It will work great, it works in constant current, or constant voltage 575v @ 500ma.

I have replaced screws like that, using needle nose pliers from the side, I have done this replacing some output transistors on old amplifiers.
The thing is new, and may not work properly, It was expensive, I would send it back,

 

[soundmotor]

It's pretty heavy, and has a brute of a transformer in it.If I can bypass the need to have a load(part of the safety system)It will work great, it works in constant current, or constant voltage 575v @ 500ma.

That really has some grunt to it. Does the pot adjust the voltage? If so, what is the range?

 

[s-petersen]

The pot adjusts the voltage or current, depending on the switch position. V 0-575 or MA 0-500. both meters show the volts and ma constantly, It was dirt cheap for a power supply.

 

[Alan0354]

I agree. It doesn't look like it would be exceptionally difficult.

It's not about how difficult only, it's about what if I screw up and burn something, it will be out of warranty, then I have to get the schematic and fix it. You really want to take this on? It's a HV SMPS.

If I fix it and burn it, I have to eat it. Why do I want to do that?

 

[whoaru99]

It's not about how difficult only, it's about what if I screw up and burn something, it will be out of warranty, then I have to get the schematic and fix it. You really want to take this on? It's a HV SMPS.

If I fix it and burn it, I have to eat it. Why do I want to do that?

What are you going to mess up by putting the screw and plate back?

Is there a concern there are other unaccounted loose parts floating around?

 

[Alan0354]

What are you going to mess up by putting the screw and plate back?

Is there a concern there are other unaccounted loose parts floating around?

No, it's how to get to the screw, You see the chassis, it's former by one piece, the front and back is not removeable. The screw is blocked by the torroid, you cannot go in from the side. Because the chassis is one piece, I have to lift both boards out of the chassis to do it. Then there are 3 pcs of edge mount pcb SOLDERED on the top big board. I always worry about dealing with these, you accidentally push it, you might crack the solder joint.




Then the picture below show there is an edge mounted pcb in the way and I have to take that assembly out before I can lift the pcb out.




It is not just put some silicon grease and screw the screw back on, only way is if I can have a right angle philips screw driver that can fit the narrow space to slowly and painfully turn the screw tight.....Which I don't have. Why do I want to do all these to save them trouble. I can wait.

 

[whoaru99]

Frankly, Alan, it looks like about a 5 minute job to me.

But, hey, it's your deal. If you have concerns about doing the job then you have to do what you're comfortable with.

 

[Alan0354]

No it's not. You tell me how to screw it in. Did you even look at the pictures and read my description? It just doesn't come out. I spent a while looking at it to determine that.

 

[s-petersen]

The way I feel, If I pay full price for something, it should be perfect, and If they wanted to make a deal, it would have to be tested working before I accepted it.

 

[Hipocrates]

small Hex nut + star lock washer + thermal paste and voila!

No need to remove the screw

 

[whoaru99]

No it's not. You tell me how to screw it in. Did you even look at the pictures and read my description? It just doesn't come out. I spent a while looking at it to determine that.

Indeed, I read it completely and said in an earlier post how I'd do it.

 

[Alan0354]

I took it apart again, looking at realistically how much room I have and check what shorter screws I have that can fit. GUESS WHAT

I know why it is like this. The screw used in the unit is TOO SMALL, it won't screw onto the heatsink. The stupid assembler must just screw without thinking, never notice it is not screwing in and just leave it. That's why the screw dropped out upon shipping!!!

Those Chinese stuffs are just something else.

I don't have the screw, it's definitely not 4-40 or 6-32. A little smaller than 6-32. I have no metric screws.

I have 6-32 shorter screw, there is no room to drill and tap another hole on the piece, only possible way is tap the 6-32 over the original hole.

But that's work again. Also, the space is very narrow, It's not going to be easy even if I try.

 

[maxhifi]

I took it apart again, looking at realistically how much room I have and check what shorter screws I have that can fit. GUESS WHAT

I know why it is like this. The screw used in the unit is TOO SMALL, it won't screw onto the heatsink. The stupid assembler must just screw without thinking, never notice it is not screwing in and just leave it. That's why the screw dropped out upon shipping!!!

Those Chinese stuffs are just something else.

I don't have the screw, it's definitely not 4-40 or 6-32. A little smaller than 6-32. I have no metric screws.

I have 6-32 shorter screw, there is no room to drill and tap another hole on the piece, only possible way is tap the 6-32 over the original hole.

But that's work again. Also, the space is very narrow, It's not going to be easy even if I try.

That's really annoying, especially for what you paid! It most likely is metric, I think Lowe's and home depot have a selection of metric screws, your choice if it makes more sense to drive there, or to the post office to send the thing back. If it were mine I'd probably fix it because I'm impatient, and then regret spoiling the warenty.

 

[soundmotor]

Get some thermal conductive epoxy and glue it on like a CPU heat sink or put it on with a tie-wrap. It's still a 5 minute job as mentioned. Or ditch it and sent it back.

How much faith do you have in it long-term after seeing the design decisions made (so far)?

 

[Alan0354]

They wrote back, they are willing to compensate me if I fix it myself. I wrote back to make sure if I screw up, they are willing to exchange for a new one. If they agree, I am going to fix it.