NYC vintage computer cap work - Page 1
Forum section: electronics / general

author: NYEngineer
author_rank: Contributor
timestamp: June 07, 2016, 03:39:25 am
content: Hi there,I have a early 1990s vintage computer. (Actually two.) I want to replace many of the caps with new, super high quality ones to keep it in good running condition for the future but don't feel up to it myself. Both in the main computer and dedicated custom monitor. Does anyone know any super reliable shops or people who could do this for me in NYC? I would much prefer not to ship.Thanks!

author: Raj
author_rank: Frequent Contributor
timestamp: June 07, 2016, 05:26:30 am
content: Quote from: NYEngineer on June 07, 2016, 03:39:25 amDigitkey? Ebay?try buying Japanese or Us brand caps though

author: Ian.M
author_rank: Super Contributor
timestamp: June 07, 2016, 05:44:53 am
content: I'm assuming the boards are through-hole technology. Probably the best bet is to find a specialist who works on vintage arcade console boards. They are more likely to appreciate the degree of care that should be taken when working on collectable technology, and less likely to do a hack job than a high volume rapid turnaround consumer electronics repair shop.

author: Len
author_rank: Frequent Contributor
timestamp: June 07, 2016, 03:43:24 pm
content: Quote from: Ian.M on June 07, 2016, 05:44:53 amOr vintage stereo amplifiers. I've seen a couple such guys on Youtube who I'd trust with vintage items, but I don't know if any are in New York.

author: edavid
author_rank: Super Contributor
timestamp: June 07, 2016, 03:58:22 pm
content: If the computers are old enough to use linear power supplies, I would leave them alone until you actually have a problem.

author: dfmischler
author_rank: Frequent Contributor
timestamp: June 07, 2016, 08:55:12 pm
content: I don't know him, butLouis Rossmanhas done a bunch of repair videos on youtube. His shop is in NYC. If he doesn't want to help you he can probably help you find somebody who would.

author: NYEngineer
author_rank: Contributor
timestamp: June 07, 2016, 09:22:37 pm
content: Thanks for the pointers and ideas. I will look around along these lines and also check out the Rossman Repair Group.I haven't looked at the hardware in detail beyond opening the covers, but I do believe it's through-hole technology.Thanks!

author: NYEngineer
author_rank: Contributor
timestamp: July 03, 2016, 04:02:01 am
content: Quote from: dfmischler on June 07, 2016, 08:55:12 pmLooks like Louis Rossman has been getting some press lately about legal problems with Apple. I wonder if that's why I haven't received any response to my inquiries.

author: retiredcaps
author_rank: Super Contributor
timestamp: July 03, 2016, 05:04:07 am
content: Quote from: NYEngineer on July 03, 2016, 04:02:01 amLouis is a member here. Seehttps://www.eevblog.com/forum/chat/apple-turning-the-thumbscrews-on-louis-rossman/msg975054/#msg975054Having watched some of this videos, in a number of them, he says he gets over 800 emails a day (even before this event). Your email is probably in his inbox with thousands, maybe tens of thousdans of others, not to mention all the youtube comments.I also seem to recall that he usually only specialises in Apple repair and usually doesn't fix other things. From his FAQhttps://www.rossmanngroup.com/faq/Are you only Mac?Yes and no. For network and server issues we can help with any platform.While we can work on PC laptops, we are limited in the services we offer. It’s nothing elitist; I wrote this entire site on my Thinkpad T520! The issue is most of the PC laptops we see cost almost as much to fix as the machine is worth and we find that people’s time constraints do not often allow for a proper estimate. It is feasible to stock most Apple laptop parts that we need, but not feasible to stock every single PC part there is, there are too many models. Considering the time constraints of our customers and the lack of ability to stock every PC laptop part there is, we’re just not best suited to servicing most PC laptops. If we feel we’re not the best fit for your issue, we will refer you to someone who is.

author: NYEngineer
author_rank: Contributor
timestamp: July 03, 2016, 01:45:56 pm
content: Quote from: retiredcaps on July 03, 2016, 05:04:07 amThanks for the details. I was thinking of physically showing up at this office address one day since my office is not far away (less than 20 blocks).My guess is that, although this is not an Apple-specific repair, it isn't actually a "repair" but rather a prophylactic replacement of thru-hole caps with appropriately rated others and so doesn't require certain knowledge of this specific gear. Furthermore, I'm totally willing to pay his proper rate to keep these computers running another several decades.Cheers,Doug

author: kwass
author_rank: Frequent Contributor
timestamp: July 03, 2016, 03:06:38 pm
content: Maybe ask Hal Guretzky if he can do it. His business is ham radio repair in Queens. I'm sure he could do it, but I have no idea if he'll work on things other than radios.http://www.landaircom.com/

author: helius
author_rank: Super Contributor
timestamp: July 03, 2016, 03:25:12 pm
content: Not exactly the same topic, but I suppose it's relevant.Is there a serious risk that a replacement electrolytic capacitor for a computer could have too low ESR? The cost of polymer (OSCON) types is not that much higher and would be a guarantee against future electrolyte leakage, but they all have lower ESR than same-sized normal electrolytics. For basic bypass caps, the lower ESR shouldn't cause any problems, except for possible peak power consumption at cold start. Resonant circuits in power supplies or clocks could go out of spec. Does anyone here have direct experience?

author: TheMG
author_rank: Frequent Contributor
timestamp: July 03, 2016, 11:22:50 pm
content: Chances are that your old computer equipment may continue to function just fine for many more years with the existing capacitors.The thing that really kills capacitors quickly in modern computer equipment is heat as well as the very high ripple currents and frequencies involved with the high current switching regulators on modern motherboards.The capacitors in early 1990's computer equipment generally ran cooler, and are under far less stress than those in modern equipment. That has a very big effect on the expected lifetime of the capacitors. So much so that at work we had mid-1990's computers in service 24/7 until they were decommissioned last year (that's about 20 years in 24/7 service!). We had a lot of those in service and the motherboards were the most reliable things in them, very very few failures and no problems with capacitors even after all that time.Unless capacitors are a known failure point for your particular equipment, or you start to experience problems, I'd say just leave them alone.

author: NYEngineer
author_rank: Contributor
timestamp: July 05, 2016, 06:35:26 pm
content: Hi all,I got in touch with someone at the Rossman Repair Group. Unfortunately, he said Louis is unwilling to replace the capacitors in my vintage computer, even if I provide them.The computer was working fine last week. This week, it's very glitchy. It literally will reboot itself occasionally just sitting there. Someone suggested that some of the tantalum capacitors could be bad, and short, then "self heal." As it turns out there are a lot of them. At least 6 on the main board, 4 on each memory card, another half a dozen on the I/O card, and six larger ones on the backplane. I really don't feel up to soldering on a two-and-a-half-decade old irreplaceable computer and need to find someone here in NYC who feels up to the task.(Capacitor info:https://www.eevblog.com/forum/repair/capacitor-identification-help/msg976893/andhttp://www.mouser.com/Search/ProductDetail.aspx?qs=ELsGmddtz%2fghnZt9oDozfQ%3d%3d)I tested the power supply under load and it is putting out reasonable voltages with ripple under 100 mV according to a Rigol DS1000E, at least on the 5V and 12V rails. (It also has -5.2V and -12V rails.)Anyone else have ideas for NYC? Any hobbyists in NYC want to help? I'll cover dinner.Thanks!

author: NYEngineer
author_rank: Contributor
timestamp: July 05, 2016, 06:45:07 pm
content: Quote from: kwass on July 03, 2016, 03:06:38 pmI gave him a ring. He only works on ham gear (which is a good thing to know if my gear ever breaks, but it hasn't in decades so...) but will be giving me the name of someone he recommends later tonight. Thanks!

author: iampoor
author_rank: Frequent Contributor
timestamp: July 06, 2016, 03:58:06 am
content: I work mostly on sensitive vintage audio gear (MANY poorly etched and deteriorating PCB's), so servicing those boards would not be a problem, but living on the other side of the country might be.If you cannot find anyone local feel free to drop me a line.

author: NYEngineer
author_rank: Contributor
timestamp: July 07, 2016, 03:39:55 pm
content: Quote from: iampoor on July 06, 2016, 03:58:06 amI think the biggest problem on these boards is that they are 4-layer boards. I have no idea how to desolder and resolder caps on this, even though they're apparently regular old tantalum through-hole caps. I assume that they somehow connect the V and GND planes of the multilayer board.You can see through the layers to the lower layers. It's pretty cool.Thanks for the offer.

author: helius
author_rank: Super Contributor
timestamp: July 07, 2016, 11:42:42 pm
content: There is no practical difference between 2-layer and 4-layer boards from a mechanical standpoint. They both have plated through holes in which the component leads are soldered. There is no physical solder bridge between the pin and inner planes.In both cases, the solder must be either removed or completely liquefied before the component is pulled, or the plating will get pulled out while it is still stuck to the lead. This requires a higher skill level to repair, and special bonding equipment (miniature rivet press). This is the reason that when the component is dead, it is widely recommended to cut its leads before attempting to desolder them. When each lead can be pulled separately, it is much easier to liquefy the solder in only that one hole. If the solder in every hole can be removed, that allows the component to be removed without damage, but that requires practice. The solder always wicks out much better when there is no pin in it.

author: iampoor
author_rank: Frequent Contributor
timestamp: July 08, 2016, 12:49:39 am
content: Quote from: NYEngineer on July 07, 2016, 03:39:55 pm4 layer boards are not any more difficult to work on if you have decent soldering equipment. Sometimes they require extra patience.Anytime!