Ive just jad the exacrly the same issue on a Linn LK140. Those small copper sleeves came out with the the capacitor connectors. I couldnt understand it, I have a very good desoldering iron.
That amp has been reworked at least once before during its life, it and a couple of other products which use the same amp board were the subject of a recall to replace those two caps with higher voltage spec parts (a reliability mod because they were too close to the limit at the top of the mains voltage tolerance range)… there’s a sticker on the base which does indicate it was done… however I’d be absolutely amazed if anyone at Linn was responsible for that abomination, they are meticulous about quality control and workmanship and if it had been damaged there, they would have fitted a new PCB… so I’d say someone has been in there since! PS, it’s pretty difficult to actually do that damage on Linn products, the PCBs are very high quality, I’ve reworked many (usually after 20 years or so of service) and never damaged one.
Not that this amf tester is without its foibles, but it's worth to note that for a 6.8mF, at 50 or 63VDC, the esr should be about 10 or 20 of miliohms at most. Half an ohm is way to high, I think and indicates wear. Sanken (subdivision of Sanyo) C3519 & A1386 outputs aren't fets, they're bipolar transistors.
@@nigelsretroworkshop Im just learning myself, so by no means an expert, if I may rec'd sth, then please take a look at through vias, but make sure they're copper, not Chinese brass, which is prone to rupture. You can get away without a press, if you're careful and ensure PCB is supported, by using two punches to gently force it open once in place. You may need to drill a clean hole to accommodate the via, but it's worth it. Once you get the hang of it, they'll look factory installed.
I think you were supposed to remove the aluminium bar associated with that one pcb, rather than the transistors. It would have avoided the broken temperature cut out. Did you consider drilling a small hole and soldering the wire bridge on both sides? I'm not sure you would have flowed solder to the top side now you have no plating
Actually I did try to remove the bar but I couldn't slide the board back far enough - the caps fouled on the casing. Leaves me wondering how they got there in the first place, I assume the original caps were shorter. I was careful with the soldering & was happy the solder had flowed through.
Hi, Difficult to see where things go, and how they work without a schematic. Just one question: the cooling strip where the outputs are mounted on, seems easy to remove. Just two inbus screws. Then you could have left the outputs attached on there, and remove that as a whole. I know, in a new to you amp isn't always easy to see how things things come apart. Creative thinking about the through hole repair, but you definatly should have soldered the topside first, and then fitting the cap. Now you have now way of knowing if the solder has flowed enough on the topside. It might have done so, but no way of knowing for sure. Strange faillure of the board by the way. Thanks for sharing. Cheers from the Netherlands.
I used to work in an industrial controls repair center. When this happened we used a brass eyelet and crimped it down . Then we soldered around the outside to the trace and left the center open. Vola a new through hole to fit the cap . just solder the cap in and you're done.
Crimping a through via would be the standard MO in my book, the only issue I can see is, that industrial quality, electrolytic copper ones, usually come in a pack of 1000.
I wouldn't be happy about the wire connection on the top side of the board under the capacitor. You cant see it to know if it is soldered. Perhaps you should have soldered it first, then fitted the cap. Large capacitors relying on only the solder connections for mechanical stability is asking for broken through-plated connections.
Nice, I've done this a few times with ILP MOSFET amp decks, they used to be really popular with mobile DJs and the caps flexed on the boards, breaking tracks and the legs of the caps.
I assumed it was maybe the result of a drop but after I filmed this video I found some old forum posts referring to a recall on this amp, specifically for these capacitors. They were changed for a higher voltage, lower capacitance - and the ones I found in the amp were the replacements so now I'm pretty certain the damage was the result of a bodged job!
@@nigelsretroworkshop If that's the case, then how come the through plating was still on the caps leg? I think the original replacement damaged the through hole plating, and a bit of bashing in the amps lifetime caused the through plating to completely break as they didn't silicone the caps to the board.
Ebay seller has 3 left Andonstar ad407 listed under AD407 without the brand name when searched. Same as Joey Does Tech YT repair uses. They have listed for 30.99 with auto coupon free ship. I thought they were an off brand but, I got mine they were legit Andonstar Ad407!!. The weird thing was they were dropped shipped from Amaz on. I sent my off brand dm201 back and kept the 407. I liked the 201 a little better but, this was half the price and did what I needed. Just passing the info and deal along.
Awesome. Somehow one of these found its way to Australia, Had it on the bench in front of me and well..... It was a bit of a mess. Some of the Links and Jumpers were not fitted but act the correct way (Video cct). It was putting out pal I not NTSC or Pal BG. Interesting is the row of sockets for tape and RGB etc are hard sockets on this one not flyleads like yours.
The ones with fixed sockets at the rear are usually the standard model rather than export.. Check the printed part number on the pcb, mine is 223,000 issue 1. Also the serial number on the underside of the case might help if it's still there
also on aliexpress they have a wide angle lens that goes on an Andonstar threaded, I wan't to try and mod it for our type of scopes. Which is a type of DM9 model made under a few different Chinese brands.
On your mantis microscope, what lens do you use for soldering ?because I have the same microscope but can’t solder under it because there not enough room. Thanks so much. Great watch as always
No mention of make/model, no link in description, no mention of the purpose of the chrome diffuser…. There is an led light ring at the tip of the camera that you did not mention. These light can cause glare which that chrome diffuser can soften. For those that want something similar sear for 7” digital microscope on aliexpress or temu
Actually there isn't a brand on the one I received but I did point to a company that sells what looks like the same one. I couldn't provide a link to the discounted price which is why I left it out. As this wasn't a paid review I didn't want to give Temu free advertising but as you say it's fairly easy to find with a search.
Re. alternative stands: A search for 'spring microscope stand' will yield purpose made stands that are an improvement over what comes in the box - they're not cheap tho. Someone else mentioned modifying an angle-poise style magnifier, I have one of those myself but I'm not convinced it would be steady enough - if it drooped, even by a mm or two, it would drive one mad :-) I think Joey-does-tech has his microscope mounted on a modified monitor stand - that would definitely take the weight, but might not have a fluid enough motion in general use? Any other ideas out there? Perhaps something based around 2020 ali strut?
Please do not buy ANYTHING from bloody Temu , if youdo or register those a-holes got ALL you're info and they sell that to other a-holes . How do you think those Chinese make profit ? Been there and have the crap quality t-shirt 🙄🙄👎👎 Take care dude .
I have a very cheap usb microscope / borescope that plugs in to the computer ... i mean its better than nothing but for doing rework having stereo vision is really nice, just got to find room on my already filled desk for a small optical one that can be had around 100 ish dollars if your keeping an eye out
For some reason, mics too close to the mouth without any kind of screen which allow the listener to hear ALL of the lip smacks and tongue noises make the video unlistenable to me, to the point of nausea. Literally trigger a queasy stomach. Had to stop watching.
That Amcap program is based on demo code for Microsoft Visual Studio. It's basically an old demo camera program to teach you how to code AV capture for Windows.
Yes, that's exactly what it reminded me of, all those useless MFC demos from back in the day. The user manual points to a download which may be better, haven't tried it as the windows app is fine for me.
Sadly I can't find a way to link to the discounted price. It regularly pops up in my instagram feed, and when you click on it it wants you to download the temu app and sign up as a new customer. Only then do you get the cheap price. Also, the app is nag-ware. I've uninstalled it until I need it again.
Turns out I bought this same microscope about 3-4 weeks ago for soldering small SMD devices. I was pretty surprised at how well it worked for how inexpensive it was. It's not great, but it's easily enough for soldering even 0402 SMD devices.
For photos and close vids, these are ok but for live work I would recommend a stereo zoom 7-40x for SMD, botany, entamology work. the mantis gives me sea sickness, i hate them, a properly used stereo is unbeatable.
Nice review. The worst part is this seems like a perfect microscope for my needs, but I refuse to buy products from manufacturers that outright lie about their specifications. 720p is perfectly fine, but if they’re going to lie, why reward it?
Search for a foundry who would be willing to make a casting of the bracket ( ideally the bracket that is still intact and have some 'cast aluminium or magnesium alloy brackets made . Have a ten or more made - keep two and advertise the others for sale.
10:08 - Lower the microscope down ? That is a redundant statement Lower the microscope implies DOWN one cannot Lower the microscope up -- or any thing else UP and at 09:59 - Raise the microscope up ? again it is a redundant statement. Read more to improve your knowledge of the English language Learn correct grammatical Legal English. That would be easily achieved by reading Law books - or take a specific course in Legal English
Glad I found you Nigel. Great review and I'll get one on order as soon as the wife's in a good mood. I'll go through the rest of your back catalogue as soon as I can and I'm looking forward to the old BBC Micro stuff. Had one of the very first Model B's and did more with that thing than any other machine since... happy days indeed. Cheers 🍺
I have a full on stereo microscope on my bench out in the garage, but I bought this exact same microscope the other day for playing around in the house. I used it to recap my Mac SE/30 the other day. I absolutely have to use a microscope for SMD work, I have problems with my eyes due to diabetes.
Yeah, it's essentially just a fancy magnifier. I have something similar but never use it. I have repaired thousands of things over 25 years and believe it or not I just use a helping-hands alligator-clip stand ($1) and an 8X stamp magnifier clipped to it and a desk lamp on a spring arm which can be put anywhere light is required. I've even mounted QFP304 chips with it. In reality you don't need more than 25mm clearance to get a soldering iron under there.
Hi think i would be inclined to put a stop at the base of the supporting rod, maybe a cir-clip to prevent the weight of the microscope from dropping down, if the two thumb wheels become loose and dropping the microscope camera head hitting the base of the unit, it does look like an error in the design, it looks quite flimsy.
I guess the remote is useful so that you dont end up knocking the thing and eother having to wait an age for the cheese bracket to stop wobbling, or have to refocus (see above about brackets made of cheese) That said, for £25, what do you expect?
I got that same microscope on Amazon. It was branded 'XCLifes' but came in the very same box. I also just use the windows camera software and don't bother with the remote. I find it works well for watch repair.
