For a couple decades I did my desoldering and removal much the way you do it. There's nothing wrong with that approach and it works. Recently I splurged and bought a nice powered desoldering station. After a few months of using it, I will never go back to the old method unless I'm in the field. It's so much safer for the board and cuts my work time easily in half. Also, if I have to remove a whole slew of transistors to test them, it's orders of magnitude easier with the station. You should consider it. Easily one of my best bench purchases ever and I kick myself for taking so long to figure that out. Anyway, I enjoy your videos and empathize with your saltiness at what you see inside amps these days. Cheers.
I'll get one eventually. But I see my buddies using them and bam, clogged. ;) If I had to recap a bunch of mixing channels it would pay for itself. And thanks!
Lyle, you may not be seeking guru status but you've become mine simply by being so straight-forward and articulate. I've played electric guitar for 55 yrs without much regard for the electronics until lately becoming more of a tone-chaser. Possibly to compensate for diminished dexterity. Your theatrical background is oddly well-suited to technical-instructional presentation: the perfect marriage of guitar and amp is a dramatic experience.
If you ever do use a spring loaded solder-sucker, I recommend lubricating the o-ring and rod with Dow Corning silicone vacuum grease. It has better lubricating properties than Apiezon-L and unlike Fomblin, it won't decompose and create acrid and toxic compounds when heated. If you also coat the spring, solder won't stick to it and it makes clearing the solder a bit easier. When I was doing field service work, using a desoldering station wouldn't have been practical, even if I wanted to try it. In most situations I found wick to be more effective, although in a few situations the solder sucker worked better.
Ah, the little details. Like looking at a component, finding the part number or specs labeling, then bending the leads so the part info is readable from the top when soldered into place. Genius. A great habit to internalize for any new build or repair work.
Thanx for showing which braid you use. I haven’t had much luck using the brands I tried. Even with a flux pen they’re still pretty hit or miss as to whether any solder will soak up. I’ll give the techspray a try.
Lyle great video no matter what amp you work on you always go the extra mile and it always show in your meticulous work you are a Master at your Craft. Thank you for all the great Videos. I’m getting ready to Recap my JCM900 mark 3 2100. I wish you were closer to me because you would be doing it for sure.
I heard the “ Shiny “ . That’s my jam it’s about the only kids movie song I’ve ever liked. The crab had some swag man , dude is balling at the bottom of the ocean .
I had to fix one for a friend last year. it had a 12ax7 in the reverb that injected too much hum in the poweramp, replaced it with a 12au7 and it got almost completely quiet and the reverb was finally usable. I also discovered that the stock tail resistor was so high value that the PI was clipping asymmetrically all the time, so i changed that too. but it took me months of trouble shooting in the spare time before i found the solution. It's a pretty common hum issue that nobody on the marshall forum could solve. Same sensitivity to moving the wires around the fx loop/reverb circuit. 12au7 in the loop/reverb. Done
Nice videography, Lyle. I can see everything. Impressive as usual. There is a little bit of a galvanic reaction between those dissimilar metals between the ring terminals & that anodized/galvanized steel chassis. A little glob of quality dielectric grease works well to slow that reaction down. Ilsco DeOxIt is a good product. You want the green stuff. Dow Corning made a very good one too. (>$$$$!!!)
This video is especially interesting as I have an old JCM 800 4210 in storage which I will be reviving as soon as I have my workshop finished so this will be really useful info👍😀
Years ago I worked at an electronics plant making radar displays for the Navy. Per their specs, the parts would fail inspection if the flat washers were installed with the flatter side up. Made life more interesting.
With the spring loaded suckers, I just always give it an extra push and release cycle or two after removing some solder. This will clear any small bits that got stuck and prevent you from having to fish out a big chunk later.
Was the "black paint" used as threadlocking compound originally red? Some formulations of that lacquer-like compound darken and become corrosive after years of heat from the tubes. Things could be worse ---- at least they didn't use Sony Bond to glue capacitors to the boards. That stuff does lots of damage to vintage audio gear: I've broken numerous dental picks over the years, scraping it off. I guess you can call it PC-board plaque.....
Nah, just black paint. Freeze spray and a heat gun are your friends with old nasty glues. Sometimes alcohol helps. If none of that gets the glue off, alcohol definitely helps.
@@PsionicAudio , freeze spray is definitely helpful. Most "canned air" (keyboard duster, etc) isn't actually air and will act like Freon if you turn the can update down and spray the glue (at work, we use Dust-Off, from Stoner). Have you worked on any guitar amps that have glue corrosion on the pc boards? I haven't seen any in your videos, though that Blues Jr had glue holding a couple of plug-in connectors in place. Annoying when you need to pull a board, but not generally problematic in that application.
@@PsionicAudio , The worst case scenario with conductive, corrosive glue is when the corrosion creeps down along the component lead and through the hole in the board. Not only do I often replace diodes and resistors (and sometimes I insulated jumper wires) where the corrosion is right up against the body of the device, but often when I remove the corroded part I find I also have to ream out the hole in the circuit board slightly in order to remove any traces of glue or corrosion down there in that hole. If you don't remove it you will often see that the solder actually *bubbles* when you solder the new replacement part in place (electrolyte leakage from capacitors can have the same bubbling effect, plus the infamous fishy smell). I have seen cases where the solder joint looks fine but the corrosion has electrically separated the component lead from the solder, inside the joint where you can't see it! I have a couple of tiny drill bits, like 1/32nd of an inch or so, chucked into Exacto-knife handles so that I can easily ream out the glue and corrosion from the holes in the board. Now if only I could find a way that one could glue foils back down to a board securely when they lift due to heat from components or a previous techs poor soldering skills.... no such high temperature glue exists that I'm aware of....
Your channel is my favorite! Thanks for your great content and taking the time to teach us some logical troubleshooting skills! Do you use a tube tester often? Would you recommend investing in one? I never see you use one or mention them in your videos. Thanks!!
Curious about your opinion on this. What year of the years they've produced these Marshall reissues did they get it right? Are the current reissues up to par with the originals?
Only had two non-1987/1959 reissues in. A 2203 and a 2550. Neither was built as well as the originals. Fixed minor issues, both amps sounded OK. Not great. Sent them home.
Filter-cap mounting clamps often come with slotted screws for the clamping tabs, or occasionally Philips. I wish they'd use Torx or Allen head screws, and Keps nuts with built-in star washers; they'd be much easier to loosen and tighten.
I remember that the first version of this circuit used red led's for clipping and discrete components for channel switching. Whereas this version used a bridge diode rectifier for clipping and an IC for switching. And I thought the nuts were the ones at Marshall that designed this thing.
Marshall could have diagonally staggered those caps too. I would have. Those pot nuts were slam stamped from sheet steel. The rounded side is the top where the punches came down & knocked out hexagon shapes with round holes. The flat-ish (cupped) side is the side where the dies sat. It's a cheap, fast & efficient manufacturing process but the end product is rather substandard.
I have a Marshall DSL40C that the sound cuts out after playing for 10 minutes. I already changed the tubes out, and took it to my local guitar tech, who changed the voltage regulator. Do you have any ideas what the problem could be? After searching the Marshall forums, I think this is a common problem. Any help would be appreciated.
Man I worked on a couple of these years ago. The board design drove me nuts, mostly because it needed new pots... the replacements are the wrong size. I have a particular disdain for this era of Marshall.
Voltage memory get interesting when it in the 100k to 22k mf ( .1 to .2 F) you can see 5 volts form on them before first use ! Below 10k not much of a problem from my point of view if they where discharged . Try rotating the clamp 180 degrees leaving the screw out in the open on the right one on the screen . Just a thought. An other very good video .
I have rotated a lot of Marshall clamps. There was a reason I didn't here but I don't recall now. I think it would have been blocked on the other side if I had.