HP DPS-600PB Internal DC Ground Removal?

[Heli_Noob]

I bought 2 of those HP PSU's and I need to make them a single 24v psu for my hyperion 720i super duo3, I charge 2x 6s 5000mah 45c batts. Anyways... Where and how do you remove the DC internally on these? Will doing so allow me to touch both units and let the 2 units touch without shorting or frying myself? I don't wanna cook myself or the power supplys. Any pictures on how to deal with the ground issues with making these two a series? If you have any pictures or help that would be very cool. How does the wiring look with the hot swap connector taken off and what wires go where to make them in series with hot swap removed? I'm not really a noob, well with electrics I am, always flown nitro but I really want to get my new 700e in the air and this is the last step. Thank you in advance for any help! PM or email mulishafmxxx@aol.com if you have any pictures of what I can do. TY!
- Nooooooob

[pctomlin]

I have seen pictures of isolating the DC side of these power supplies, but I can't find then right now. They were in a post at RCGroups, RR or Tjinguy. I came across them when I was researching to build my charging box. From what I remember you cut two jumper wires that are the ground for the front left screw that holds the board to the chassis, and you have to score the upper and lower side of the board for the right front hold down screw to break the ground traces in the board itself.

[Heli_Noob]

thanks, i'll give it a shot today

[Heli_Noob]

grrr, jumpers snipped and clear of each other, 1/4 hole through both mounts, isolated the post on the case, isolated the board over the two mount holes with rubber garments.... case is still showing signs of DC on both my meters. Also on the power cable.... Am I supposed to snip that green/black wire and isolate it? It's the wire that leads to the ground on the power plug. There are also blue resistors on them, should any of those be taken away? I've seen so many pictures of people removing and isolating that green/black wire, but i keep getting conflicting info but i've moved from step 1 to step 2 lol

[J DAMAGE]

1/4 hole, push grommet through hole so the grommet is isolating the top and bottom of board, srew main board back in case , you will still get ground at all 4 srews to case because case is grounded through ac to case, check continuity under grommets to case, ( should show no ground) then check main board ground post to case ( should show no ground ) look at the drawings i sent to you.

[Heli_Noob]

noob reply... made a video... on 200m and 20 shows negitive DC voltage readings, is that correct? the gronded PS shows 12.7

video i made showing my meter testing both units
http://www.youtube.com/watch?v=Ni2uFqyXKV0

[007brendan]

I have the same power supplies. Here's a pic of how I removed the DC ground. There are two screws on the DC side that attach the board to the case. The right one you can unscrew. I took it out and surrounded it in heatshrink to break the link.

The left screw has no chance of being removed without unsoldering the lead posts from the board, but luckily, it connects to ground through two metal jumpers on the board, they're underneath the lead posts, you can see where I've cut them in the pic below.

[J DAMAGE]

You can take the left screw out once you unscrew the break-out board, 2-screws on poss&neg post, 2-screws L&R of break-out board and 1-nut center of break out board, and ribbin cable unlocks from housing.

[Lighty]

I just removed the ground from one of the power leads..

[007brendan]

Originally Posted by Lighty

I just removed the ground from one of the power leads..

That removes the AC Ground. Removing DC is safer, and you don't have to isolate the cases to prevent them from shorting out.

[Lighty]

Hey Brendan

I fixed up the AC ground so it's back to normal and proceeded to remove the DC with two nylon washer on both DC mounting screws. I left the jumpers intact.

I tested them and don't trust them touching each other, the multi meter which is set on AMPS reads 0.00 on the modified unit. On the unmodified unit the meter isn't constant, I get 0.00 - 0.06 0.03... Is this safe?

I didn't connect the charger just yet..

[007brendan]

Originally Posted by Lighty

Hey Brendan

I fixed up the AC ground so it's back to normal and proceeded to remove the DC with two nylon washer on both DC mounting screws. I left the jumpers intact.

I tested them and don't trust them touching each other, the multi meter which is set on AMPS reads 0.00 on the modified unit. On the unmodified unit the meter isn't constant, I get 0.00 - 0.06 0.03... Is this safe?

I didn't connect the charger just yet..

Set your multimeter to read volts. Plug in just the modified unit. If the ground is still intact, you should get 12V between the case and the positive terminal. If the ground is removed it will be 0V, or will jump around zero. There should be 0V between the PS cases, so there should be no problem with them touching. Once you connect the PS's in series you should see 24-25V between the case of the modified PS and its positive terminal.

[Lighty]

Sorry I didn't explain my test, I just simply with the meter placed the + & - on the outside of each case. This read was not from the - or positive poles.

Ok I just tested it again this morning and noticed that the + on the meter wasn't all the way in.

I put the + & - on the outside of the case on the modified unit = 0.00 (amps & DCV)

I put the + & - on the outside of the case on the unmodified unit = 0.00 (amps & DCV)

I put the + on the modified and - on the unmodified unit = 0.00 -0.01 ( amps & DCV)

Does this seem look ok?

[Lighty]

I'm charging a pack off it now and it reads 25.34v off the 306b. 0.0amp. This must be due to the very small pack 800mah lipo.

But they aren't touching....

[007brendan]

Originally Posted by Lighty

Sorry I didn't explain my test, I just simply with the meter placed the + & - on the outside of each case. This read was not from the - or positive poles.

Ok I just tested it again this morning and noticed that the + on the meter wasn't all the way in.

I put the + & - on the outside of the case on the modified unit = 0.00 (amps & DCV)

I put the + & - on the outside of the case on the unmodified unit = 0.00 (amps & DCV)

I put the + on the modified and - on the unmodified unit = 0.00 -0.01 ( amps & DCV)

Does this seem look ok?

Let me see if I understand this, you're connecting both multimeter leads to the outside of the same case? You do realize that is basically the same as just touching the leads together, right? It doesn't measure anything.

Also, don't worry about trying to measure amps. You don't measure it the same way you're measuring volts anyway.

It almost sounds like you probably shouldn't be making these modifications. However, it sounds like you lucked out, because if you hadn't removed the DC ground, you would have shorted out the first PS when you plugged them in and it (hopefully) would have automatically shut itself off.

The cases are both connected to AC ground, so the cases are already "touching" through the wall outlet. The fact that the cases aren't physically touching doesn't matter.

[Lighty]

Cheers Brendan. All good they are touching and getting it on. A HUGE thanks to J DAMAGE!

Cheers

[thanasi]

Hi Guys i need some help !!
I have been folowing these threads and ckd others but have not able to find any answers.
Im allready running a DPS-600pb thanks to Tjin but wanted to try series for 24v as im planning to get (hoping) a t-550 for Christmas.
Now i removed my hot-swap on my first ps so i wanted to do the same for the second (24v). My problem is when i remove the ground on the right side my power sp doest fire up, clicks on and off like its in cuircuit protection ?
When i re connect no problem but i get the DC ground wich we dont want.
I believe its something with the ribbon connector im missing a step ????
If you look at my pic i ( from left (red) to the right ) i joined the first 2 to ground and 4,5 and 8 shorted to gether. I left purple and blue un att as my first power supp and all works norm BUT when i remove the right side grnd it clicks.
I also cut the jumpers in this case as described in previous posts.
I tried some diff ways, removed the red wire (pair) from ground and same thing so i re inst.
I cant seem to remember where i found the info for removeall of the hot swap so i just opend my first PS and followed what i did there.
Any help will be greatly appreciated
Thanks

Sorry about the upside down pics lol took with phone !

[J DAMAGE]

Looks like the ribbin cable is wired wrong,

[thanasi]

Thanks for the reply !!
Can you describe the ribbon connections starting from the red wire, left to right.
Red being the left side.
I just matched the first supply that has been working for me for 6 months now !

[rlclemmons]

I had the same issue last night, click.click.click. The red wire (1) and the one next to it (2) need to be connected to DC ground. Then 4,5,8 must be connected together.

Looking at that pic, move your (1,2) ring terminal to the lower stand-off marked JGND. If you have removed dc ground from your chassis, that's why she is not powering on.