- Uniden Bearcat BC855XLT Schematic - 2 Updates
- F-connector has unstretchable outer covering. - 3 Updates
- weather instrument barograph ink resource and pen modification? **UPDATE** - 1 Update
- how to repair this circuit board? - 13 Updates
- MOV I.D. Help please - 1 Update
| Michael Terrell <terrell.michael.a@gmail.com>: Feb 03 01:18AM -0800 > Hi, > This is NOT a handheld unit. I should have mentioned > that. Uniden has always refused to sell me any manuals. They claimed their consumer grade C-band equipment couldn't be repaired outside the factory. I laughed and told them it was a toy compared to the receivers we built. One thing was certain. It was too complex to repair without a manual. thet3/4" hole burnt through the circuit bord was impossible to reverse engineer. About 30 parts nd a lot of missing traces, along with the substrate. Have you contacted H.W. Sams? (Photofacts) They might have something. They used to publish scanner manuals. |
| Ken Layton <KLayton888@aol.com>: Feb 03 07:56AM -0800 > I had searched the web for a source about a year ago. > Does anyone know where I can get a schematic? > Thank You in advance, John Back in 1995, I was able to order the manual from their parts department. It is Uniden part number SMBC855XLT (also known as part number 12A90-3AT200). It is 54 pages long, but the copy I purchased back then was missing pages 19 and 20. I contacted Uniden and they copied the missing pages and sent them to me. Back then the manual cost $16.00 plus $4.50 shipping from Uniden's parts department. If you can't get the manual from Uniden any longer, I could photocopy the manual, but it's got about ten 11 x 17 full sized schematics. It's a very comprehensive manual which covers everything and even has voltage measurements. |
| micky <NONONOaddressee@rushpost.com>: Feb 02 05:57PM -0500 In sci.electronics.repair, on Sun, 2 Feb 2020 05:22:36 -0800 (PST), >https://www.amazon.com/GE-Coaxial-Connector-Weather-73512/dp/B003YKG9FS >If you must do it this way, I'd give it a little coating of dielectric grease before threading it all together. >Probably last 10 to 20 more years assuming the cable is in good shape. Thanks. When I was doing all this, I bought the hexagonal crimping pliers that look like pliers. Sometime since, maybe at a yard sale, I found the one that look like some advanced weapon, and has more leverage, also with 2 hexagonal holes, but I don't think I've ever had a chance to use it. This is my chance. |
| Michael Terrell <terrell.michael.a@gmail.com>: Feb 03 01:50AM -0800 On Sunday, February 2, 2020 at 8:22:39 AM UTC-5, John-Del wrote: > > because of the age, 35 years, and the occasional heat**, the white > > vinyl covering doesn't stretch enough to replace the F-connector. > > What to do? Cut off an inch or two and install a new connector properly. You can add a short jumpper and connect it with a F-61 adapter. You may find that the cable is beyond reuse due to age rather than heat. Some cheap brands used too little plasticizer, so it has evaporated and the the sheath is cracking. Jersey Specialty and Radio Shack both come to mind for this failure. I used to maintain CATV head end equipment for a major MSO and I specified what bulk supplies to buy. We only bought Belden or Times coax for our drop and premise wiring. If the old cable isn't any good and not nailed down I have stripped the end of new and old cable and used a Western Union splice on the center conductors to pull in new coax. It helps to spiral a piece of thin electrical tape over the open part, but if the holes are big enough you can shake he coax and get it through the hole. > First determine if it's RG59 or 60, RG6, not 60 |
| Michael Terrell <terrell.michael.a@gmail.com>: Feb 03 01:53AM -0800 On Sunday, February 2, 2020 at 5:57:17 PM UTC-5, micky wrote: > found the one that look like some advanced weapon, and has more > leverage, also with 2 hexagonal holes, but I don't think I've ever had a > chance to use it. This is my chance. As long as the dies aren't worn the second tool is the one you want. There are even fancier tools with interchangable dies for specific cables and connectors They are quite expensive. We used them for some custom microwave cables at on job. |
| Jeff Liebermann <jeffl@cruzio.com>: Feb 02 07:09PM -0800 >any trace at all until uploading the photo... I did turn the drum a day >ahead to get past the huge ink spot): >https://imgur.com/a/GcYaO8c <https://www.metcheck.co.uk/blogs/barographs/156686919-how-to-get-a-good-barogram> All the items mentioned apply. I was using and recommending ink absorbent paper. According to the above URL, that's wrong. It did work for me, but wasn't very good looking. However, it didn't create a huge ink blob. At this point, I don't know exactly what is wrong. It could be wrong ink, wrong type of paper, bad nib spacing in the pen, bent nibs, etc. Dunno. I don't have a barograph handy for testing. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
| Abe D <abednpspam@verizon.net>: Feb 02 11:44AM -0500 On 2/2/20 8:32 AM, John-Del wrote: > It's too late now but repairing board with a topical coating of epoxy is not the way to stabilize it. The epoxy acts like a top hinge and the bottom of the board will flex away from the crack. To make it more stable, you have to add some epoxy on the other side and hope it adheres. > The proper way to repair a fractured board is to remove any component(s) that crosses the break, and fit the board pieces back together where the seam doesn't even show. You may actually have to break the board a bit more to get it to fit perfectly. > At this point, apply FRESH cyanoacrylate so it wicks inside the fracture and bonds the board completely together from the inside, not just one side. Not totally clear to me here. Am I going to try applying more epoxy on the board side of the crack, cyanoacrylate, or both? > If done properly, the cracks will be barely visible. Scrape the green mask off the trace just at the break and half the distance the trace is wide. A drop of solder across each land will finish it. What about the large, outer section of the board appearing more like a screen rather than solid trace? I doubt I could find stranded wire wide enough and pretty fragile there to try scraping. Also, what's the best tool for the scraping? > In your case, because the pieces don't fit that well, scrape back the mask and hand wire from point to point and across the fracture with some fine copper stranded wire (one or more strands depending on width of the trace), and coat the entire trace with solder using the copper strand as a sort of "rebar". > Deflux the board and apply either a conformal coating or get some green nail polish to protect the lands. Nail polish would be a go, but what to use for defluxing? Thanks. |
| Ralph Mowery <rmowery28146@earthlink.net>: Feb 02 12:06PM -0500 In article <r16ua5$7ce$1@dont-email.me>, abednpspam@verizon.net says... > > In your case, because the pieces don't fit that well, scrape back the mask and hand wire from point to point and across the fracture with some fine copper stranded wire (one or more strands depending on width of the trace), and coat the entire trace with solder using the copper strand as a sort of "rebar". > > Deflux the board and apply either a conformal coating or get some green nail polish to protect the lands. > Nail polish would be a go, but what to use for defluxing? Depends on the flux used. Most of the time use IPA . That is alcohol that is 90% or better with no addatives that is often in common rubbing alcohol. The common rubbing alcohol that is 70 % would be ok except most of it contains other chemicals that leave a residue on the boards. |
| etpm@whidbey.com: Feb 02 09:32AM -0800 On Sun, 2 Feb 2020 02:47:18 -0500, Abe D <abednpspam@verizon.net> wrote: >Unfortunately, the board cannot be replaced. >Thanks in advance. >Abe I think some JB weld formulations have very fine metal powder in them for strength. Maybe you should see if the stuff you used is conductive before you apply power to the board again. Eric |
| John-Del <ohger1s@gmail.com>: Feb 02 10:16AM -0800 On Sunday, February 2, 2020 at 11:44:57 AM UTC-5, Abe D wrote: > > At this point, apply FRESH cyanoacrylate so it wicks inside the fracture and bonds the board completely together from the inside, not just one side. > Not totally clear to me here. Am I going to try applying more epoxy on > the board side of the crack, cyanoacrylate, or both? I had two avenues of advice: the first how to properly repair a cracked or totally broken PC so it's virtually invisible, and advice directed to you having already attempted a repair with epoxy. Because you have already epoxied the board together, it's really too late to use the cyano adhesive, particularly if you put epoxy into the crack. We never want to use cyano as a filler. The beauty of cyanoacrylate is that it doesn't require a gap in order to put the epoxy in. With cyano, you can fit the board together perfecly and the cyano will wet *into* the PC (either glass or phenolic) and bond it with no gap whatsoever. Properly done, there is virtually no gap across the broken foil and the foil ends butt together almost perfectly. If you can remove the epoxy you already put down, and there is no epoxy in the break line, then you can refit the pieces so the crack is perfectly joined and virtually invisible. At this point, you can use cyanoacrylate to permanently bond the board internally, as opposed to using external adhesive. If done properly, no jumpers are even required as the mask can be scrapped off right at the crack and a dot of solder put across the gap. Because the board is bonded internally, there is is virtually no flex and the solder ball will make a perfectly clean and virtually indestructible connection across the break. If you can't remove the epoxy, you're better off adding a layer to the bottom to reduce the "hinge" effect you will get with epoxy on one side or the other allowing flexing. As for the large areas of damaged foil, you can add strips of solder wick braid to add some physical strength as well as complete the circuit. |
| Tempestinatesttube <tempest@ina.com>: Feb 02 01:58PM -0500 On 2/2/20 1:16 PM, John-Del wrote: > I had two avenues of advice: the first how to properly repair a cracked or totally broken PC so it's virtually invisible, and advice directed to you having already attempted a repair with epoxy. > Because you have already epoxied the board together, it's really too late to use the cyano adhesive, particularly if you put epoxy into the crack. We never want to use cyano as a filler. The beauty of cyanoacrylate is that it doesn't require a gap in order to put the epoxy in. With cyano, you can fit the board together perfecly and the cyano will wet *into* the PC (either glass or phenolic) and bond it with no gap whatsoever. Properly done, there is virtually no gap across the broken foil and the foil ends butt together almost perfectly. > If you can remove the epoxy you already put down, and there is no epoxy in the break line, then you can refit the pieces so the crack is perfectly joined and virtually invisible. At this point, you can use cyanoacrylate to permanently bond the board internally, as opposed to using external adhesive. Too well bonded now, even though not perfectly aligned. And I did use some cyano on the board side just a little while ago to fill in. Not the best idea for sure and it's only about 49 F in the room where the board is, so I better wait a full day before doing anything else. > If done properly, no jumpers are even required as the mask can be scrapped off right at the crack and a dot of solder put across the gap. Because the board is bonded internally, there is is virtually no flex and the solder ball will make a perfectly clean and virtually indestructible connection across the break. The board rejoining is too imperfect for solder dots. Looks like I will be using jumpers and solder braid, removing flux afterwards, and covering with nail polish. > If you can't remove the epoxy, you're better off adding a layer to the bottom to reduce the "hinge" effect you will get with epoxy on one side or the other allowing flexing. I'm going to glue a couple of round wooden sticks along each length of the board on the underside. There will be one horizontal stick along each edge. This won't interfere when I reinstall the board. Hopefully it will help augment any strengthening needed. > As for the large areas of damaged foil, you can add strips of solder wick braid to add some physical strength as well as complete the circuit. Solder braid, good idea. Don't have any though, will have to order some. What's the best way to remove the conformal coating? |
| Tempestinatesttube <tempest@ina.com>: Feb 02 02:27PM -0500 > for strength. Maybe you should see if the stuff you used is conductive > before you apply power to the board again. > Eric No conductivity, so thumbs up there. Thanks for pointing that out. Would have hated to go through all this only to realize I was shortchanged by the epoxy. |
| Tempestinatesttube <tempest@ina.com>: Feb 02 02:35PM -0500 On 2/2/20 12:06 PM, Ralph Mowery wrote: > no addatives that is often in common rubbing alcohol. > The common rubbing alcohol that is 70 % would be ok except most of it > contains other chemicals that leave a residue on the boards. Have both 70 and 90, so thumbs up, thanks! |
| Tempestinatesttube <tempest@ina.com>: Feb 02 02:36PM -0500 On 2/2/20 2:35 PM, Tempestinatesttube wrote: >> The common rubbing alcohol that is 70 % would be ok except most of it >> contains other chemicals that leave a residue on the boards. > Have both 70 and 90, so thumbs up, thanks! Maybe not so thumbs up when I read more clearly. Standard ISO is all I have. What about Everclear? |
| etpm@whidbey.com: Feb 02 12:37PM -0800 On Sun, 2 Feb 2020 14:27:47 -0500, Tempestinatesttube >No conductivity, so thumbs up there. Thanks for pointing that out. >Would have hated to go through all this only to realize I was >shortchanged by the epoxy. Yeah, that would suck. |
| John-Del <ohger1s@gmail.com>: Feb 02 01:06PM -0800 On Sunday, February 2, 2020 at 1:58:34 PM UTC-5, Tempestinatesttube wrote: > Solder braid, good idea. Don't have any though, will have to order > some. What's the best way to remove the conformal coating? I just use a jeweler's screwdriver that's not knackered up. If it has a crisp edge, you can easily scrape off the conformal coating (if the board has it) as well as the green solder mask. Expose the copper and use a bit of flux to improve the wetting and bonding of the solder to the copper. |
| Tempestinatesttube <tempest@ina.com>: Feb 02 04:21PM -0500 On 2/2/20 4:06 PM, John-Del wrote: >> Solder braid, good idea. Don't have any though, will have to order >> some. What's the best way to remove the conformal coating? > I just use a jeweler's screwdriver that's not knackered up. If it has a crisp edge, you can easily scrape off the conformal coating (if the board has it) as well as the green solder mask. Expose the copper and use a bit of flux to improve the wetting and bonding of the solder to the copper. Very good, thanks again. Will tackle this tomorrow once I have the braid in hand. |
| Tom Biasi <tombiasi@optonline.net>: Feb 02 08:51PM -0500 On 2/2/2020 11:44 AM, Abe D wrote: >> green nail polish to protect the lands. > Nail polish would be a go, but what to use for defluxing? > Thanks. JB weld is conductive. |
| Fox's Mercantile <jdangus@att.net>: Feb 02 08:05PM -0600 On 2/2/20 7:51 PM, Tom Biasi wrote: > JB weld is conductive. I found that out the hard way. I replaced a thermal fuse on a crystal heating oven. Turned the power on and Blam! It took a bit to clean that mess up. -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com |
| whit3rd <whit3rd@gmail.com>: Feb 02 04:24PM -0800 > from the lathe 1980s. Today there was a big power surge and one of the > 3 MOVs on the input for the drive exploded. > The marking on one MOV is ENB401 40. It just needs to outlast the fuse, so the exact ratings aren't too important. Assuming 220V three phase, just about anything in this list will do the task. <https://www.digikey.com/products/en/circuit-protection/tvs-varistors-movs/141?k=MOV&k=&pkeyword=MOV&sv=0&pv2151=u250V&sf=1&FV=-8%7C141%2C16%7C339262%2C16%7C339263%2C16%7C339265%2C16%7C339266%2C16%7C339267%2C1989%7C0&quantity=&ColumnSort=0&page=1&pageSize=25> There's also the NTE resource to find equivalents, <https://www.nteinc.com/search.php> which suggests a replacement part, but that part number was an old Fuji one, and not really available nowadays (except 'new-old-stock' at outrageous prices). |
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