MichalD very nice upgrades! I am trying to make something similar, but I have a problem.

I replaced all electrolytic caps in the pre-amp board and I noticed a short in the position of this cap.



I removed the cap and the short remained. The pads of this cap are shorted, even without a cap in place. Is this normal? Can you check please?

Hi, thanks for the fast response. On the photo on the right, the missing connector (with the 12 pins) is the only thing that I didn't replace in this pcb. But I did replace the jst connector on the left, that comes from the power supply board. On that connector pins 2 and 3 are also shorted, which is also weird. Can you check if you have any shorted pins on that connector please?

I will test more tomorrow and try to follow the traces on the pcb.

Fortunately I found the short... A big solder blob had dropped on the pcb and I hadn't noticed. I removed it using a pair of tweezers as it wasn't stuck well on the components.




And here's a pic of the pcb with the new caps on. Nichicon Fine Gold and Nichicon Muse bipolars (sorry for the blurness).



This post has been edited by nautilus7: Jun 29 2018, 12:01 AM

Hi, thanks for the help.

The 2x6 pin connector in the pre-amp is still in good condition. I bought a replacement, but I chose not to put it in. I replaced the 2x6 connectors on the power amp boards though. They were oxidized. It was a pain in the ass to unsolder them and I slightly damaged the pads...

I have almost finished upgrading my Gigaworks set. The set was working fine, so it isn't really a repair, but an upgrade. Anyway, I guess it was a matter of time it would stop working because of the low quality capacitors used, so I chose to proceed. Following the great guide of MichalD, I replaced all electrolytic caps in the power supply board, as well as in the audio amp boards. Here are some photos of the finished amp boards.

Hi, thanks!

I glued them not because I was afraid they will fail/break, but mainly because they are too close together and they can hit each other and vibrate. Don't forget they are inside a sub-woofer!

I used silicon (neutral cure, non corrosive) not glue, btw.

I don't think there is a service manual... Only a schematic of the power board.

What is your problem? Is there anything that seem damaged on the boards?

This post has been edited by nautilus7: Oct 11 2018, 06:25 AM

Perhaps a visual inspection of all parts, especially in the power supply board, will reveal the problem. I can't tell from the video.

Some photos of the boards might help.

This is my restoration, which I did in 2018 (took about 5 months). I followed MIchalD's instructions and suggestions, who I would like to thank publicly as well.

My gigaworks set did not have any problem (it was working fine, except from the relay clicking issue), since it hasn't played for so many hours though. I thought it would eventually show the same problems as most users here are facing, so I decided to go on with the restoration.

Some things worth mentionng for my restoration:

I replaced all electrolytic and cheap ceramic capacitors in the psu board as well as in the audio processing and the power-amp boards. I also replaced all connectors, some cables, diodes, the power switch and maybe even more parts I forget now. The total cost was about €200 and around €100 more for some tools I needed. All electronic parts were bought from Mouser. It may sound too much, but the restoration is certainly possible with less money (for example changing only the electrolytics on the psu board).

I changed the mounting orientation of the psu board, both in the L-shaped bracket (in a way that the heatsinks make contact with it) and also in the backplate, so I can use it for heat dissipation. In addition, I put thermal paste in between all metal parts (the L-shaped bracket, the power amp heatsinks and the external heat sink).

Where the psu board was damaged (the solder mask was destroyed by the corrosive glue used for the capacitors) I reapplied UV curable solder mask (bought from ebay). For the mains input capacitors, some of the pads were destroyed when removing the caps, so I used external wires in the back of the board to connect them properly.

Finally, I covered the subwoofer box with 8mm thick felt. Among with the new caps in the the audio boards, I think it sounds a little bit better now.

Thanks! I have completed the restoration since last October I think, but I didn't have time to post the pictures. Of course, the relay clicking issue is fixed for good!

@paleta, your top243 doesn't look good... and the 470uF caps also seem bulged too, like MichalD said.

This post has been edited by nautilus7: Feb 22 2019, 06:04 AM

No, the parts are not the same. What parts do you need? Are you planning to replace all caps (electrolytics and ceramic)?

I am not sure I understand what you mean about digikey. You have to manually select one-by-one your products, put them in the shopping cart, and order them. At least that is what I did when buying from Mouser.

The electrolytic caps me and MichalD used are high quality, long life, low ESR caps from top brands like Rubycon, Nichicon, Panasonic, Nippon Chemi-con.

This post has been edited by nautilus7: Apr 8 2019, 07:57 PM

Hi, mouser, digikey, etc send each part in separate plastic bag with a sticker/label with exact product specs and code numbers. Don't worry about this.

MichalD's electrolytics are low ESR. I don't know what digikey says, but you can also check the product specs (pdf) that comes directly from the manufacturer.

Replacing caps with bigger capacity ones isn't necessarily good or bad. It depends on the purpose of the capacitor.

For example the mains input caps (470uF 200V) can be replaced with bigger ones and basically all electrolytics can be replaced with bigger ones, if I remember correctly, since their purpose is to act as current "banks". Bigger ones can provide more current, or more correctly "current with less ripple". If this will actually make any difference, I don't really know. Also you have to consider the size, because bigger caps may not fit. Also, if you replace existinf caps with much higher capacity ones, maybe you have problems with the RC time constant.

In other caps like some high voltage ceramic ones, their value is carefully selected in relation to a resistance to form a snubber network to filter the higt voltage spikes created by the transformers. So you shouldn't change the value of these.

Also, every low voltage ceramic cap is connected in parallel with one electrolytic. This is a trick to have low ESR value, without using high quality low ESR caps. So theese ceramics don't need to be quality/expensive ones, but anyway.

My mouser parts list:


Also for the audio boards and for the control pod:




In some cases (in ceramic and audio caps) I ordered more than what is needed in case something goes wrong when soldering, etc.
Also for audio caps I used higher voltage caps, as long as I didn't have any problems with space/size.

I hope I didn't forget anything...

This post has been edited by nautilus7: Apr 10 2019, 09:42 AM

Thanks.

If your are really a perfectionist, you would search all parts we propose, find alternative, newer or better parts, compare and then decide what to buy!

All parts (mine and michalD's) are from respected manufacturers, and similar in performance. Some are overkill (like the avx ar ceramics - I would probably choose the cheaper sr series if I were to buy again), some are absolutely necessity, like the mains input filter caps.

That being said, I think my electrolytics are a little bit better, except for the Panasonics, where I think MichalD's Rubycons are better.

Mouser doesn't sell Rubycon anyway, so I had to search for another model and I ended up with the Panasonics (which I did not bought from mouse btw, but from another shop, much cheaper).

Hi, I was listening some music the other day... I only used 2 satellite speakers (stereo) and sub of course.

I cranked the volume quite high for testing... I can't remember my gigaworks playing so loud in the past I believe...

This post has been edited by nautilus7: Apr 12 2019, 07:33 PM

About the fuse, I bought ceramic fuse, quick blow, 3.15A, 250VAC, 5x20mm.

MichalD is correct as always.


Even if you replace the parts that look damaged, I think you should investigate further what caused the problem.

Perhaps when you did your original repair, you didn't scrape off all the degraded glue, and now it has turned conductive and started blowing things?

This post has been edited by nautilus7: May 3 2019, 07:57 PM

Yeah, you're welcome!

Well done.

@djozmo, I can't remember 100%.

These are bipolar caps. If you can't find any 1uF bipolar in the audio processing boards or in the audio amplifier boards, then it should be in the control pod. I remember it also has a couple bipolar caps.

This post has been edited by nautilus7: May 15 2019, 08:34 AM

Can you post any pictures? Maybe the faulty components are visible. The psu schematic is here: https://forum.lowyat.net/index.php?act=Atta...post&id=4355159

Why so many posts asking the same thing?

There is no schematic for other boards.