Products > Test Equipment
Any better way to use a HP 6625A than dragging cables from the rear outputs?
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Berni:

--- Quote from: DC1MC on May 26, 2021, 06:57:33 pm ---Hey @German_Engineer mod inspired me as well to order the posts and I'll do the modification on my 6627A if the ever present Deutsche Adler will not confiscate them. The question is, does anybody know of a suitable silent fan because the always-on on, maximum speed, one is making way to much noise.
Also I want to add temperature drive speed control and eventually the output on/off switch (Option 750, see the attached PDF.

Also @German_Engineer, can I bribe you  ^-^ to print me a set of decals, if so, kindly please PM me.

Cheers,
DC1MC

Link to posts, they really loon nice:
https://www.aliexpress.com/item/32871905530.html?spm=a2g0o.store_pc_groupList.8148356.63.6c305068emoWQL

--- End quote ---

I just used a generic Corsair 12V PC case fan.

The fan that is originally in there is way overkill for the amount of cooling this thing needs in a typical lab environment (Its designed to run 24/7 packed in a hot rack on a hot factory floor). So due to the huge heatsinks you can get away with much less powerful of a fan. Id avoid the really silent low rpm PC fans, but any regular fan where you can feel a decent amount of airflow with your hand should be fine. Yet no need to go for those special high CFM fans since those tend to be ridiculously powerful and make a lot of noise.


--- Quote from: james_s on May 27, 2021, 03:02:23 am ---I really hate drilling holes in nice equipment, I've passed up gear more than once because some former owner had drilled holes in the front panel for some modification. How about just make a box that sits under, on top or next to the thing that has binding posts? You could even have the PSU up out of the way on a shelf above the bench with a little remote panel on or under the bench with binding posts in a convenient place.

--- End quote ---

These large rack mount PSUs are not really all that high valued pieces of gear. They sell so cheap that shipping one cross country costs more in shipping than they are even sold for. They are bulky and don't really provide that much power compared to there size, so they are not all that desirable. So i don't really care if i made it even less desirable. Certainly wouldn't do this to a more high valued piece of gear.

My solution for rear connectors on gear is to put bulkhead feedtrough connectors on the rails of my server rack (i keep all the big boatanchors in there). I often don't properly rackmont my gear and instead use rackmount shelves. So this leaves lots of the square mounting holes down the side rails free and they are large enough to fit things like SMA connectors trough them. So i just bought some SMA to BNC bulkhead connectors and screwed them into these square holes, then ran a SMA cable out the back to the back of the gear. Never looked into any high power versions of this, for something like the 50A PSU in that rack i just ran a big fat cable from the back and fold it together on top of the PSU when not in use.
German_Engineer:
Hi DC1MC, have fun with the mod.

The stickers are a bit tricky and I needed three loops until I got them right. I used "Film Free Waterslide Decal Paper Type M" (USD 8.90 for 10 sheets) and glue W2 (USD 6.00). I ordered the items directly from sunnyscopa in KR. Their website is perfect, Paypal, and the delivery took just a few days - much faster than aliexpress. They have some youtube videos describing the application. Unlike other waterslide decals, the film is removed at the end. Only the toner and the glue remains on the front panel. The result is very similar to the original print/silk screen. I think they are unique and are also good to repair front panels with rubbed-off markings.

Site: https://sunnyscopa.com/
Paper: https://sunnyscopa.com/collections/waterslide-decal-paper/products/filmfree-waterslide-decal-paper?variant=36426713727142
Glue: https://sunnyscopa.com/products/glue-w1-w2?variant=36426927734950

Tricky items: The paper needs to be printed mirrored on a laser printer. I managed this with ppt and a pdf printer driver from the "PDF-Xchange" toolset which has a mirror option. The printer driver did change the scaling slightly and I had to adjust it to preserve the holy 19mm spacing between the posts. Tip: Print first on paper and measure the distance between two posts. Grey color (some black pixels on white background) rubs off. It is better to print as much toner as possible (Black or any other saturated color, heavy paper, high quality setting of the printer). The stickers should be aligned with the bottom edge of the front panel. The rest is dexterity and patience for placing them at the correct position, wipe out the excess glue, heat with a hair dryer and let them dry. After a few trials they will be good. You can remove them with isopropanol and some ellbow grease without damaging the equipment. I did not dare to use acetone as the company recommends. I attach a ppt file with the stickers, so you can modify the labels to fit the 6627A. Just download and rename the extension to pptx (no virus, I hope).

Fan: I am happy with the noctua fan I mentioned in my post. Temperatures in the 6626A (150W total) are good. The 6627A has 160W , I believe, and should be OK as well. Sound level: 45dBA 50cm in front of the device and no disturbing resonances or harmonics. The 12V header can be located in the service manual. I bought a fan controller https://de.aliexpress.com/item/32973504131.html?spm=a2g0s.9042311.0.0.31a44c4d3LPhRu but did not try it since i need a good idea where to place the temp sensor. Anyhow, the power supply shuts down when it overheats and displays an error message according to the manual - so it is safe to experiment.

The next move in the beauty contest would be a backlight for the LCD  ;) anyone?
DC1MC:

--- Quote from: German_Engineer on May 27, 2021, 09:34:08 am ---Hi DC1MC, have fun with the mod.

The stickers are a bit tricky and I needed three loops until I got them right. I used "Film Free Waterslide Decal Paper Type M" (USD 8.90 for 10 sheets) and glue W2 (USD 6.00). I ordered the items directly from sunnyscopa in KR. Their website is perfect, Paypal, and the delivery took just a few days - much faster than aliexpress. They have some youtube videos describing the application. Unlike other waterslide decals, the film is removed at the end. Only the toner and the glue remains on the front panel. The result is very similar to the original print/silk screen. I think they are unique and are also good to repair front panels with rubbed-off markings.

Site: https://sunnyscopa.com/
Paper: https://sunnyscopa.com/collections/waterslide-decal-paper/products/filmfree-waterslide-decal-paper?variant=36426713727142
Glue: https://sunnyscopa.com/products/glue-w1-w2?variant=36426927734950

Tricky items: The paper needs to be printed mirrored on a laser printer. I managed this with ppt and a pdf printer driver from the "PDF-Xchange" toolset which has a mirror option. The printer driver did change the scaling slightly and I had to adjust it to preserve the holy 19mm spacing between the posts. Tip: Print first on paper and measure the distance between two posts. Grey color (some black pixels on white background) rubs off. It is better to print as much toner as possible (Black or any other saturated color, heavy paper, high quality setting of the printer). The stickers should be aligned with the bottom edge of the front panel. The rest is dexterity and patience for placing them at the correct position, wipe out the excess glue, heat with a hair dryer and let them dry. After a few trials they will be good. You can remove them with isopropanol and some ellbow grease without damaging the equipment. I did not dare to use acetone as the company recommends. I attach a ppt file with the stickers, so you can modify the labels to fit the 6627A. Just download and rename the extension to pptx (no virus, I hope).

Fan: I am happy with the noctua fan I mentioned in my post. Temperatures in the 6626A (150W total) are good. The 6627A has 160W , I believe, and should be OK as well. Sound level: 45dBA 50cm in front of the device and no disturbing resonances or harmonics. The 12V header can be located in the service manual. I bought a fan controller https://de.aliexpress.com/item/32973504131.html?spm=a2g0s.9042311.0.0.31a44c4d3LPhRu but did not try it since i need a good idea where to place the temp sensor. Anyhow, the power supply shuts down when it overheats and displays an error message according to the manual - so it is safe to experiment.

The next move in the beauty contest would be a backlight for the LCD  ;) anyone?

--- End quote ---

Well, if I can't convince you to print some for me for a cost, I have to suffer with my ancient Epson Acculaser :(, but I'll try my best, approximately what distance from the panel  bottom line did you use ? I now use some of those distribution boxes with posts as some other member mentioned, but they are occupying space on my little desk and a bit painful to drag around, so this mod is most welcome if it will succeed. any special precaution that I should take while disassembling ? What is the size of the fan ?

 Cheers,
 DC1MC
German_Engineer:
Here the decals for the 6627A. The pdf contains the mirrored version for printing the decal at 100% scaling or "no scaling". Use the highest resolution. The posts must be 19mm apart. The other file is a pptx (download and change the extension from txt to pptx). It contains the drawing (1st slide) and a picture with the positioning of the decals (2nd slide).
German_Engineer:
Last and final mod for this one (The nerd-factor is already too high :) ): An EL strip as backlight https://www.ebay.de/itm/263120517911.
The idea came from other posts in the forum showing this mod on a 3468A multimeter. The EL strips have a limited lifetime, so the beauty will fade. The mod is not difficult and I made just two mistakes:
(1) I cut an EL strip with scissors and the layers delaminated. This led to an uneven brightness (Can be fixed with a flattening iron, someone said). Then I tried a paper cutter on the next strip and it turned out good.
(2) On the back of the LCD glass sandwich is a polariser film and a mteal plated reflective tape. The reflective tape needs to be removed and replaced by the EL-strip. I took a razor scraper and boldly removed both of them. Later I had to separate the  reflective tape and the polarizer to fix the problem. It would have been better to insert the scraper between the polarizer and the reflective tape... BTW, the glue came off after applying plenty ethanol and let it soak for 10 minutes. A microfibre cloth did the rest. Have fun.
 
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