Not a good idea to pull both transformers and swap. As jazznut states this is probably where it was messed up in the first place. I would only pull the bad side and check the transformer with an ohm meter and trace out the PC board. The transformer is probably OK and you most likely have an issue on the PC board.
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A question Ted:
when the PSU for the analog board is external and the bridge removedā¦are still all 4 heatsinks of the internal PSU used or only 2 of them (which ones)?
I just want to have a guess how hot or not the unit then still would get.
Iām not precisely sure, there are three 5V supplies, I believe one for the display, one for the bridge and one for the digital card. And thereās a 12V supply. They donāt use the power transformerās windings symmetrically. The Bridge probably draws more than the digital card. I donāt know how much compared to the display. All four are rated for 1A each. I donāt have a good guess how much heat any given system would be dissipating, especially since the largest determinant in the supplies for the analog and digital cards is the AC input voltage.
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Thanks Ted! Since the use of an external PSU for the analog board, the front two heatsinks are clearly less hot. Before that, they were hot to the touch, just as the back ones still are. Just like in a big class A amp. Much too hot imo for a closed housing.
I didnāt remove the bridge yet, but will do to try its SQ influence when an external streamer of a friend is connected. Then I will also see how much colder the back heatsinks get or if the front heatsinks get completely cold.
I understood the heatsinks get hotter in a 230V unit than in the US version?
Do any of these voltage rails go low in standby mode? What happens in standby mode?
As far as I know only the display is switched off.
Here in Europe (the UK is no longer in the EU) there are rules that suggest about 0.5w in standby. However, things get sold here where standby just switches off virtually nothing so the component continues to draw current. Iāve resorted to using remote controllers to properly remove power from devices such as my TVās subwoofer.
I think itās more then just the screen as I hear several relays click.
Ted?
Standby mutes and turns the screen off. The relay clicks you hear are the mute relays.
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Thanks Ted.
My friendās psaudio ds became a victim of cargo. We tried my screen part to detect the error, so my screen didnāt work either.
@tedsmith
PS Audio service are the best people to help on non-digital card/non-analog card problems. I donāt have any experience with, say, common screen failures.
I live in Turkey.
You can get in touch with our distro out there Audiogen High End. Ibrahim is our guy out there and he is great to work with! Iāll DM his email to you now.
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In case heat dissipation is nameable different for 120 vs 230V, this would explain the different feedback especially regarding the DS jr. at the time. Iād be generally interested if there are measurements made with components with closed housings to ensure durability of parts, especially if AC voltage is different from the home voltage of the producing company. I donāt expect that there are long term tests made, but maybe not only a rough awareness of the temperature inside. But maybe this is only relevant for a few electrolytic caps.
120V vs 240V (vs 100V) isnāt the issue. If the system has linear power supplies and has to be able to run at 120V - 20% (96V) then any voltage up to 120V + 20% (144V) has to be able to be dissipated as heat - thatās what having a linear power supply implies.
The DS Jr does run hot, but not hot enough to shorten life of the system. It uses quality caps designed for higher voltages and also derates those caps significantly (e.g. lower voltage swings at a lower temperatures and voltage than the parts are speced for.)
What my previous message was trying to convey is that if your nominal voltage is, say, 125V then the supplies for the digital and analog boards will have dissipate 8% more heat than if it were running at 115V.
Of course we know the temps in the boxesā¦ The Jr was hotter than we liked in itās smaller box, but not beyond acceptable values. And yes itās only really a problem for non-solid aluminum electrolytic caps. Everything else is happy running over 100 or 120 degrees C (and much higher for many components.) I take into account the temperature of all components over all expected room temperatures and input voltages with careful simulation in Spice (including small things like keeping temperature rises in traces and vias below 2 degrees C.) I also choose components with low temperature coefficients so the sound character wonāt change with changes in room temperature or whether the box below the DAC is on or not.
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Thanks much, understood. 120 vs 230V produces the same heat as long as both are equally within their spot. It may be ridiculous, but somehow I worry about that heat 24h a day in that closed box, even if itās just for those few electrolytic caps. Itās just because I have no clue how long an electrolytic makes it at continuous 120F? inside (the heatsinks have 140F), especially as some of them are placed directly besides the heatsinks.
140F is 60C which is fine at the heat sinks.
Take a look at the Lifetime at Temp. column:
https://www.digikey.com/en/products/filter/aluminum-electrolytic-capacitors/58
Not so long ago many caps were rated at about 1000 to 2000 hours at 85C. The lifetime doubles for each 10C drop of temperature.
I usually use caps rated at 2000 or 5000 hours at 105 or 125C. A cap rated at 2000 hrs at 125C has an expected life of 20 years of continuous use at 140F. If the cap is āonlyā 2000 hrs at 105C thatās 5 continuous years. But the lifetime is often defined by the value of the cap drifting by about 25%. Considering that aluminum electrolytic caps often are rated with a 20% tolerance, the cap isnāt going to fall over dead or explode at the rated lifetime.
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Ok, 20 years would be fine, but the 5 years of those 105/2000 degree caps would be over in my case 
But as thereās not 105 degree inside, itās fine, too. I read after clicking on one, that those behind the link are 1000 hours at 105ā¦Are the normal non SMD elkos at the power supply also rated 105 or even lower?
Take a look by searching for electrolytic caps at digikey (or Mouser, etc.) There are many choices and most manufacturers are going to use the ones that make sense.
My last point in my previous post was that even 5 years of life is fine. The cap is still working fine, it just wonāt filter the AC quite as much, but the difference is way below the design limits of the power supply.
BTW, my DS has a heatsink at 140F, but the hottest cap is 40C so if that was a cap that was only 5 years at 140F the lower temp would extend itās life to 20 years. In practice other things will go wrong by then. I donāt know which caps the DS power supply is using, but Iām not worried.
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