On 10/23/2022 1:27 PM, Antonio Carlini via cctalk wrote: It looks like the RIFA caps I've removed from my DEC H7864 P/S. Though mine were colored more toward the amber you find dead flies fossilized in and had visible cracks in the case.  The RIFA logo/name was on one side with other markings on the other side, on the top was only the X2 and the value. You might have to remove it just to be certain that it is a RIFA, but the top lettering and the overall look point in that direction. -- John H. Reinhardt

On 23/10/2022 20:19, John H. Reinhardt via cctalk wrote: On 23/10/2022 22:18, Peter Coghlan via cctalk wrote: You are both right: I desoldered it tonight and it is indeed a RIFA: https://photos.app.goo.gl/smYWrNeuFeo6Ragw7. I measured it as: 28mm W x 16mm D x 13mm H. There are a couple of matches so I'll probably buy a few from each of these: https://www.bitsboxuk.com/index.php?main_page=product_info&cPath=65_81&… https://www.ebay.co.uk/itm/124149363651 the bitsbox one may be a teensy bit to large but the ebay one should fit nicely. Neither is too expensive even with postage so I'll buy a few, given that I do have a fair few PSUs knocking around. I have four H7868-B modules (two per BA213) that don't work and two of them have leaking caps, and I mean *seriously* leaking!. This PSU though (the H7822-00) is currently OK: None of the caps show any sign of leaking or bulging. Given how easily the RIFA popped out, I might speculatively try removing one of the 1800uF ones just to see what it looks like underneath, and maybe measure its value too. Mouser wants £1.10 each (for 10+) and also charges £12 minimum shipping, digikey seems similar; eBay does have a UK seller doing 10 for £6, which might be a better option if I need to go that way. Antonio -- Antonio Carlini antonio(a)acarlini.com

On 24/10/2022 21:07, Antonio Carlini via cctalk wrote: I thought those things that hold the fans on were a variation on pop rivets but now that you mention it, I can see the "three sided slot" on the outside. Perhaps there is something preventing them from unscrewing, so that vibration from the fans will not end up loostening them or something like that? I've taken the boards out of a whole bunch of H7821 and H7822 PSUs to replace the electrolytics without removing the fans. It was difficult at first but the more I did, the easier it got. I did come across one seized fan along the way but I haven't a replacement yet so I haven't got around to removing the bad one. I should look into it. Regards, Peter Coghlan.

Antonio Carlini via cctalk wrote: The LED is more than just a power on indicator. When it fails to light, it can indicate that something is not right in the PSU. It may tie in with the "power good" output from the PSU. It could be that it is failing to light because the regulation is not working properly because there is no load. I'd try it with a load before anything else. The H7822 may need a load on both boards. To eliminate the LED from enquiries, you could try powering it from a 5V supply via a 1KOhm resistor or something like that to see if it lights. If it does, then further investigation in the PSU may be required. If the LED does turn out to be bad, I forget whether it comes out by pulling the LED out of the bezel first or taking the ring off the rear of the bezel first, whichever works. It was only the 1800uF 25V capacitors were bad (mine are all brown too). In an earlier posting I said there were six of them in a H7821 and ten of them in a H7822. I should have said five in a H7821 and nine in a H7822. The 470uF 400V capacitors in my units were all fine. The leaking electrolyte had damaged some other components in some cases, especially an odd value resistor which seems to have different values in different units, something around 464 Ohms. It is in series with an thermistor which seems to control the speed of the fans. I've also had a zener diode fail which caused problems with the fans. (If the fans aren't operating properly, the LED might not light!) Regards, Peter Coghlan.

On 15/11/2022 10:06, Antonio Carlini via cctalk wrote: My experience with a H7822 is that when all the diagnostic LEDs stay lit, DC OK is probably not getting asserted so the power supply might still not be working 100% correctly. In the H7822, DC OK seems to be the purple lead and high (something around 4V-5V) means asserted. Regards, Peter Coghlan.

On Wed, 2 Nov 2022, Peter Coghlan via cctalk wrote: It does. I have an H7821 PSU where the LED lights briefly upon power-on and then goes dark. The PSU cannot be used to power a mainboard as it does not come up, however it works just fine with storage in an expansion box. It is one of those that I recapped after leaks have appeared; in fact it is the one that made me aware of the problem in the first place. I'll have to get back to it sometime to get this sorted. There's a 2Ω dummy load on the 5V line in storage expansion boxes powered by the H7821, so these do require minimum current to work correctly. Same here, five 1800uF 25V caps to replace in the H7821 according to my notes. Overall if you spot a cap that says SXF on it, then replace it right away whether already leaking or not. These were made by Chemi-con. Other Chemi-con lines reported problematic are SXE and LXF, though from own experience they seem less prone. Also Nichicon PL and PF parts may have to be replaced, I have seen the former ones actually leaking in other DEC PSUs, such as the H7826, which is also infested by SXF parts in various capacitances. Both kinds leaked in a generic industrial Bel Power PSU used with a Cisco device. Sadly the problem with component shortage has hit capacitors as well and some that used to be readily available are not anymore and prices have risen too. NB I wasn't aware about the problem with RIFA capacitors, it seems like I might have to replace them in several PSUs I have already recapped, sigh. I haven't seen any of them fail though, not at least in an obvious way. HTH, Maciej