ESR.. I know that ESR is important these days, but..

What if I tell you guys that my father, who worked with electronics for more than 30 years, never really cared about it? 😀
- In fact, I had to spell out that ESR acronym to him first, because he didn't recognize it first time ("Ah yes, that nonse, I see.")

That being said, he was no beginner by any means.
He used to work with linear amplifiers (CB/HAM radio), built and repaired lots of 13.8v power supplies with 20 amps onwards (both transformer/transistor based).
In his youth he had a holiday job at a radio/electronics shop and repaired TVs and radios, too.

What he did, what others did, back in the day, was to use bigger capacitors with higher voltage ratings. For higher tolerance.

Sure, it's frowned upon these days. But it worked.
Some of the stuff he built still works, with the big old electrolytic capacitors still in place. 😀

Where are you going to get the new caps from? Depending on that I can recommend specific replacements.

Rubycon YXG are still being made and they're very good, so if you can buy them it would be ideal as they are an exact replacement. For the LTec and the Taicon PW you can also use YXG, it has similar specs. These seem to be the caps on the output so it's where ESR really matters, you want to keep relatively close to the value of the originals.

The Taicon specs don't show the ESR values for the VR and VT series because they're general purpose caps, which means you can basically use any good 105C rated equivalent. The series naming for Taicon caps (VR, VT, PW) should be the same as Nichicon ones as it was a joint venture at one point... so you can just get the Nichicon equivalents for those.

Same deal for the 2 big Nichicon caps, just get whatever snap-in caps of the same specs from a well known manufacturer. For these 2 it doesn't really matter if they're 85C or 105C... they shouldn't be under a lot of stress.

Jo22 wrote on 2022-08-16, 18:41:

ESR.. I know that ESR is important these days, but.. […]
Show full quote

ESR.. I know that ESR is important these days, but..

What if I tell you guys that my father, who worked with electronics for more than 30 years, never really cared about it? 😀
- In fact, I had to spell out that ESR acronym to him first, because he didn't recognize it first time ("Ah yes, that nonse, I see.")

That being said, he was no beginner by any means.
He used to work with linear amplifiers (CB/HAM radio), built and repaired lots of 13.8v power supplies with 20 amps onwards (both transformer/transistor based).
In his youth he had a holiday job at a radio/electronics shop and repaired TVs and radios, too.

What he did, what others did, back in the day, was to use bigger capacitors with higher voltage ratings. For higher tolerance.

Sure, it's frowned upon these days. But it worked.
Some of the stuff he built still works, with the big old electrolytic capacitors still in place. 😀

Older power supplies were usually just fine with general purpose capacitors, especially linear ones and even some switching ones. But for more "modern" (by this I mean around the mid '90s or so) stuff it becomes necessary, I don't think the engineers that design them ask the manufacturers to use low ESR caps just because they feel like it.

Regarding voltage ratings: once you're past a certain safety threshold (say, using 16V caps on a 12V line) I don't think using caps rated for a higher voltage is going to help you much. If you see over 16V on a 12V rail consistently then a blown capacitor is going to be the least of your worries. And good luck trying to fit larger caps into enclosed spaces.

The linear power supply cared less but they tolerance large range of capacitors used but the old age solution was use very large uF capacitor or several to exchange to help with power demands surges due to low frequency ripples (60hz or 120hz due to rectifier bridge for lack of technology that we are used to these days today.

Cheers,

TheMobRules wrote on 2022-08-16, 18:55:

Regarding voltage ratings: once you're past a certain safety threshold (say, using 16V caps on a 12V line) I don't think using caps rated for a higher voltage is going to help you much.

16v caps were exactly among the most troublesome, if memory serves.
Since most vintage 12v equipment really operated with 13,8v in practice (lab PSUs), it was near the maximum specifications.
Using 25v caps or even better, 50v caps, was safer.

TheMobRules wrote on 2022-08-16, 18:45:

Where are you going to get the new caps from? Depending on that I can recommend specific replacements. […]
Show full quote

Where are you going to get the new caps from? Depending on that I can recommend specific replacements.

Rubycon YXG are still being made and they're very good, so if you can buy them it would be ideal as they are an exact replacement. For the LTec and the Taicon PW you can also use YXG, it has similar specs. These seem to be the caps on the output so it's where ESR really matters, you want to keep relatively close to the value of the originals.

The Taicon specs don't show the ESR values for the VR and VT series because they're general purpose caps, which means you can basically use any good 105C rated equivalent. The series naming for Taicon caps (VR, VT, PW) should be the same as Nichicon ones as it was a joint venture at one point... so you can just get the Nichicon equivalents for those.

Same deal for the 2 big Nichicon caps, just get whatever snap-in caps of the same specs from a well known manufacturer. For these 2 it doesn't really matter if they're 85C or 105C... they shouldn't be under a lot of stress.

I was planning on using either digikey or mouser , I think digikey might have more stock though?

OK, here you go, these are the Digi-Key part numbers (please check the dimensions, you don't want to buy caps that don't fit!):

AppleSauce wrote on 2022-08-16, 18:19:

Nichicon 85c LU(M) 560uf 200v Ripple 1960
Nichicon 85c LU(M) 560uf 200v Ripple 1960

Replace with Nichicon LGU 560uF 200V
493-2701-ND

AppleSauce wrote on 2022-08-16, 18:19:

LTec 105c LZG 1500uf 16V Ripple 1920 Impedance 0.030 0.070

Replace with Rubycon YXG 1500uF 16V
1189-1723-ND

AppleSauce wrote on 2022-08-16, 18:19:

Rubycon 105c YXG 2200uf 10V Ripple 1910 Impedance 0.031 0.12

Replace with Rubycon YXG 2200uF 10V
1189-1062-ND

AppleSauce wrote on 2022-08-16, 18:19:

Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17 Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17 Ruby […]
Show full quote

Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17
Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17
Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17
Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17

Replace with Rubycon YXG 2200uF 6.3V
1189-1761-ND

AppleSauce wrote on 2022-08-16, 18:19:

Rubycon 105c YXG 470uf 25V Ripple 1050 Impedance 0.069 0.27

Replace with Rubycon YXG 470uF 25V
1189-1735-ND

AppleSauce wrote on 2022-08-16, 18:19:

Rubycon 105c YXG 470uf 16V Ripple 840 Impedance 0.087 0.35

Replace with Rubycon YXG 470uF 16V
1189-2192-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c PW 470uf 10V Ripple 550 Impedence 0.117 0.525

Replace with Nichicon UPW 470uF 10V
493-1743-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VR 100uf 16V Ripple 160

Replace with Rubycon ML 100uF 16V
1189-2182-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VT 47f 25V Ripple 90
Taicon 105c VT 47f 25V Ripple 90

Replace with Rubycon YXJ 47uF 25V
25YXJ47M5X11-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VT 10uf 50V Ripple 50
Taicon 105c VT 10uf 50V Ripple 50
Taicon 105c VT 10uf 50V Ripple 50

Replace with Rubycon ML 10uF 50V
1189-2305-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VT 2.2uf 50V Ripple 18

Replace with Rubycon YXJ 2.2uF 50V
50YXJ2.2M5X11-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VT 1uf 50V Ripple 12
Taicon 105c VT 1uf 50V Ripple 12

Replace with Rubycon YXF 1uF 50V
1189-3764-1-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VT 0.47uf 50V Ripple 7

Replace with Rubycon MH5 0.47uF 50V
50MH50.47MEFC4X5-ND

I tried to prioritize exact replacements for the caps on the secondary side to match ESR of the originals as much as possible, for the others I just chose the cheapest that was available from good manufacturers. You could further optimize the total cost if you do some research and find cheaper equivalents for the YXG.

TheMobRules wrote on 2022-08-17, 00:30:

OK, here you go, these are the Digi-Key part numbers (please check the dimensions, you don't want to buy caps that don't fit!): […]
Show full quote

OK, here you go, these are the Digi-Key part numbers (please check the dimensions, you don't want to buy caps that don't fit!):

AppleSauce wrote on 2022-08-16, 18:19:

Nichicon 85c LU(M) 560uf 200v Ripple 1960
Nichicon 85c LU(M) 560uf 200v Ripple 1960

Replace with Nichicon LGU 560uF 200V
493-2701-ND

AppleSauce wrote on 2022-08-16, 18:19:

LTec 105c LZG 1500uf 16V Ripple 1920 Impedance 0.030 0.070

Replace with Rubycon YXG 1500uF 16V
1189-1723-ND

AppleSauce wrote on 2022-08-16, 18:19:

Rubycon 105c YXG 2200uf 10V Ripple 1910 Impedance 0.031 0.12

Replace with Rubycon YXG 2200uF 10V
1189-1062-ND

AppleSauce wrote on 2022-08-16, 18:19:

Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17 Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17 Ruby […]
Show full quote

Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17
Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17
Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17
Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17

Replace with Rubycon YXG 2200uF 6.3V
1189-1761-ND

AppleSauce wrote on 2022-08-16, 18:19:

Rubycon 105c YXG 470uf 25V Ripple 1050 Impedance 0.069 0.27

Replace with Rubycon YXG 470uF 25V
1189-1735-ND

AppleSauce wrote on 2022-08-16, 18:19:

Rubycon 105c YXG 470uf 16V Ripple 840 Impedance 0.087 0.35

Replace with Rubycon YXG 470uF 16V
1189-2192-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c PW 470uf 10V Ripple 550 Impedence 0.117 0.525

Replace with Nichicon UPW 470uF 10V
493-1743-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VR 100uf 16V Ripple 160

Replace with Rubycon ML 100uF 16V
1189-2182-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VT 47f 25V Ripple 90
Taicon 105c VT 47f 25V Ripple 90

Replace with Rubycon YXJ 47uF 25V
25YXJ47M5X11-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VT 10uf 50V Ripple 50
Taicon 105c VT 10uf 50V Ripple 50
Taicon 105c VT 10uf 50V Ripple 50

Replace with Rubycon ML 10uF 50V
1189-2305-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VT 2.2uf 50V Ripple 18

Replace with Rubycon YXJ 2.2uF 50V
50YXJ2.2M5X11-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VT 1uf 50V Ripple 12
Taicon 105c VT 1uf 50V Ripple 12

Replace with Rubycon YXF 1uF 50V
1189-3764-1-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VT 0.47uf 50V Ripple 7

Replace with Rubycon MH5 0.47uF 50V
50MH50.47MEFC4X5-ND

I tried to prioritize exact replacements for the caps on the secondary side to match ESR of the originals as much as possible, for the others I just chose the cheapest that was available from good manufacturers. You could further optimize the total cost if you do some research and find cheaper equivalents for the YXG.

Oh hey thanks a bunch that probably took out a whole bunch of your time so I really appreciate the help since I'm a bit of a noob when I comes to picking caps.
I'll go through and double check the dimensions , luckily I measured all the caps with calipers so that shouldn't be too difficult.
Also I wouldn't worry too much about cost , I think the minimum order for free shipping from digikey is 60 dollars aud so I figured I might as well splurge some money and get better caps since I wouldn't save that much money with the shipping cost anyways if I wanted to penny pinch.

Oh btw does anyone know what this diode looking thingy is on the underside of the pcb?

TheMobRules wrote on 2022-08-17, 00:30:

OK, here you go, these are the Digi-Key part numbers (please check the dimensions, you don't want to buy caps that don't fit!): […]
Show full quote

OK, here you go, these are the Digi-Key part numbers (please check the dimensions, you don't want to buy caps that don't fit!):

AppleSauce wrote on 2022-08-16, 18:19:

Nichicon 85c LU(M) 560uf 200v Ripple 1960
Nichicon 85c LU(M) 560uf 200v Ripple 1960

Replace with Nichicon LGU 560uF 200V
493-2701-ND

AppleSauce wrote on 2022-08-16, 18:19:

LTec 105c LZG 1500uf 16V Ripple 1920 Impedance 0.030 0.070

Replace with Rubycon YXG 1500uF 16V
1189-1723-ND

AppleSauce wrote on 2022-08-16, 18:19:

Rubycon 105c YXG 2200uf 10V Ripple 1910 Impedance 0.031 0.12

Replace with Rubycon YXG 2200uF 10V
1189-1062-ND

AppleSauce wrote on 2022-08-16, 18:19:

Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17 Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17 Ruby […]
Show full quote

Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17
Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17
Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17
Rubycon 105c YXG 2200uf 6.3V Ripple 1650 Impedance 0.042 0.17

Replace with Rubycon YXG 2200uF 6.3V
1189-1761-ND

AppleSauce wrote on 2022-08-16, 18:19:

Rubycon 105c YXG 470uf 25V Ripple 1050 Impedance 0.069 0.27

Replace with Rubycon YXG 470uF 25V
1189-1735-ND

AppleSauce wrote on 2022-08-16, 18:19:

Rubycon 105c YXG 470uf 16V Ripple 840 Impedance 0.087 0.35

Replace with Rubycon YXG 470uF 16V
1189-2192-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c PW 470uf 10V Ripple 550 Impedence 0.117 0.525

Replace with Nichicon UPW 470uF 10V
493-1743-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VR 100uf 16V Ripple 160

Replace with Rubycon ML 100uF 16V
1189-2182-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VT 47f 25V Ripple 90
Taicon 105c VT 47f 25V Ripple 90

Replace with Rubycon YXJ 47uF 25V
25YXJ47M5X11-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VT 10uf 50V Ripple 50
Taicon 105c VT 10uf 50V Ripple 50
Taicon 105c VT 10uf 50V Ripple 50

Replace with Rubycon ML 10uF 50V
1189-2305-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VT 2.2uf 50V Ripple 18

Replace with Rubycon YXJ 2.2uF 50V
50YXJ2.2M5X11-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VT 1uf 50V Ripple 12
Taicon 105c VT 1uf 50V Ripple 12

Replace with Rubycon YXF 1uF 50V
1189-3764-1-ND

AppleSauce wrote on 2022-08-16, 18:19:

Taicon 105c VT 0.47uf 50V Ripple 7

Replace with Rubycon MH5 0.47uF 50V
50MH50.47MEFC4X5-ND

I tried to prioritize exact replacements for the caps on the secondary side to match ESR of the originals as much as possible, for the others I just chose the cheapest that was available from good manufacturers. You could further optimize the total cost if you do some research and find cheaper equivalents for the YXG.

Hey I looked at the sizes and some of them were a bit off as was some of the ripple , so i modified the list a bit , do you reckon this one should work alright?

Yes, it should be OK. Don’t get stuck trying to match ripple current exactly, especially for the small caps. There are factors I didn’t mention such as temperature and frequency that affect the rating but the idea is to be in the ballpark, i.e. get the same “type” of cap as the original.

Not sure about Kemet electrolytics as I don’t have experience with them, but for a 47uF I guess it’s fine. Usually I restrict my search to Nichicon, Panasonic, Rubycon and Chemi-con.

>and the values seem a bit inconsistent

electrolytic caps have 10% tolerance to start with

Jo22 wrote on 2022-08-16, 18:41:

What if I tell you guys that my father, who worked with electronics for more than 30 years, never really cared about it? 😀
- In fact, I had to spell out that ESR acronym to him first, because he didn't recognize it first time ("Ah yes, that nonse, I see.")

back in the day everything used linear power supplies, only aerospace/military and maybe medical was SMPS until eighties where computers picket it up

Jo22 wrote on 2022-08-16, 18:41:

He used to work with linear amplifiers (CB/HAM radio), built and repaired lots of 13.8v power supplies with 20 amps onwards (both transformer/transistor based).
In his youth he had a holiday job at a radio/electronics shop and repaired TVs and radios, too.

all linear power supplies , low est is a detriment and can even destabilize output

rasz_pl wrote on 2022-08-18, 09:37:

electrolytic caps have 10% tolerance to start with

More like +/- 20%

majestyk wrote on 2022-08-18, 09:57:

rasz_pl wrote on 2022-08-18, 09:37:

electrolytic caps have 10% tolerance to start with

More like +/- 20%

I just wanted to mention that. I bought a set of Nichicon caps for repairs, with the most common values, and they all have 20%. Many seem spot on, but several that I tested show 10% deviation or more.

Okay well I ended up adding in the new caps in but I'm not 100% happy with the solder job I did.

Couple of nitpicks , I ended up bridging two legs but I couldn't get them to un-bridge for the life of me , the legs are on the same trace , so is this something that needs to be undone or not?

Also I underestimated the difficulty of soldering the snap on caps , I ended up needing to crank the iron to 400c along with using a chisel tip and a buncha flux , and I still went pretty poorly , I'm worried I spent to many attempts and too long flowing the solder , is there a chance that I killed the big input caps?

Looks fine to me, dont worry about aesthetics. Polarity, no accidental shorts and solid solder joints is all that matters.

Well I tried to boot up the psu but it refused to start , I know its the psu because I swapped this one for another one and then the pc magically turned on.

I'm not sure specifically what I've done wrong , but there's alot of possibilities.

I'll have to open the psu up again and try and troubleshoot it I guess.

Hope you took pictures of the psu before the mod for comparison 😀

The PSU is ATX right? First thing I would check is if you have 5V on the standby line (purple wire usually) when you flip the switch. If there's no voltage at that point then probably there's a short somewhere and the PSU is in protection mode, in some cases you can also hear a high pitch sound and/or the fan tries to spin up for a second.

Carefully go over each joint you soldered, also checking the capacitor orientation, post pictures if you're not sure. Also look for solder blobs that may have spilled over parts of the PCB.

Regarding your earlier question about the big caps, it's strange, I never had issues soldering these at around 350C or even with a crappy 40W iron. Besides, it's a single sided PCB, I don't think it would sink a lot of heat compared to a motherboard for example. Maybe your iron was oxidized or not making proper contact with the pads/legs?