Fender Silver Face Twin Restoration - Part 2
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- Опубліковано 24 тра 2024
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/ @bradsguitargarage
Webpage: www.bradsguitargarage.com.au
Facebook: bradsguitargarage
Instagram: / bradsguitargarage
Equipment:
Soldering:
Pace MBT station w/SX100 & PS-90 handpieces
Hakko 474 w/815 handpiece
Hakko 936 w/907 handpiece
Hakko FX-888D w/FX-8801 handpiece
Quick 861DW hot air station
BOFA fume extraction unit
Loctite Multicore solder (C511 / 362)
Test Equipment:
Fluke 11, 175, 177 & 179 handheld DMM's
Tektronix 2236 analog oscilloscope
Rigol DS-1054z digital oscilloscope
BK Precision 4017A sweep / function generator
BWD 160a function generator
HP 6236B triple output DC power supply
Kyoritsu 3132A insulation / continuity tester
Video equipment:
Overhead cam: Panasonic HC-V785 w/Audio Technica AT9946CM mic
Handheld cam: Panasonic DC-G85 w/Olympus M.Zuiko Pro 12-40mm f/2.8
On location cam: Panasonic DC-GH5s w/Panasonic-Leica 9mm f/1.7 & 12-60mm f/2.8
Capture card(s): Magewell HDMI USB, ATEN UC3020-AT, ATEN UC3021
Headset Mic: Audio Technica BP892xcW-TH
Lapel Mic: Rode Go
Editing: Adobe Premiere Elements
Hand Tools:
Wiha, Felo, Stanley screwdrivers
CK & Engineer cutters / pliers
RS Pro wire strippers
Sidchrome & Gear Wrench spanners, sockets & shifters
Veritas planes & chisels
Materials / Consumables:
JJ's / TAD electron valves
Elixir / Ernie Ball / D'Addario / Rotosound strings
Electrolube & DeoxIT cleaners, lubricants & chemicals. - Наука та технологія
Definitely appreciate your approach to repairs. Too many techs rush to get the amps out quickly and ignore items that could see the amp back on their bench in a matter of weeks or months. The “no boomerangs” philosophy may not make the money the rush job techs do…but at least you can sleep well at night knowing you do business the right way!
That's right, mate.
Pretty embarrassing to have a rig go down in the middle of a set.
I want my peeps to play with confidence and focus on losing themselves in their art.
I do what I can to make that happen.
Glad you decided to replace those parts Brad.. We've gone this far, so excited it's getting done right. Looking forward to getting her back x
Sometimes I wish I still had my 71 super reverb, and sometimes I see videos like this .. 😅
Love this kind of video. You and Lyle are doing some of the best amp content on youtube.
Yeah, I miss my '70 Super Reverb - my back doesn't
Had mine 25 years and sold it to pay the mortgage 20 years ago...
Back in 1977 I saved up to purchase a brand new Twin Reverb,
I dragged that amplifier with me everywhere, through Hell and Back as well as 2 Wives, and I still own it! I play it regularly, the filter caps have been replace 3 times! Speakers and tubes, changed so many times I can't even be sure how many sets I've burned through. A super tough amp, very well made.
wow not only is the amp reborn, you've diligently erased a very hard last third of its life! Thats a ton of great work Brad!
One thing that doesn't go through these videos is the smell of tasty vintage solder... Its like well aged whiskey :D One thing I'd definitely recommend to vintage amp owners is do a yearly/regular checkup even if there is no apparent issue, its worth it imo.
Not so much a repair as some kind of nightmare kit build with bad parts and no instructions! Legendary.
I thought I would add my own findings. I stripped a fibreboard from a SF Twin Reverb of similar age. The board had up to 30 volts present in some locations. I used a heat gun to remove wax and cleaned the board with isopropyl alcohol twice. I partially repopulated the board and wired it into the amp. In some areas there were huge improvements but the fibreboard was still conductive. I suspect if you have very small DC voltages on the board then cleaning the board may work, if it doesn’t then either a new board or tag strip is required.
G'day Brad,
It's good to finally see someone who understands what a restoration really is, particularly in the YT guitar/music community. I'm looking forward to the rest of your videos on this amp.
As a side note regarding dirt on electrical components for you - I was showing an apprentice mechanic the voltage leakage on his old HK 186 Kingswood one day. With a DMM, I showed him that there was 9 volts leaking through the dirt & acid, between the negative terminal & the battery's plastic case. I can imagine how much 75% of the B+ is on an amp like this.
Keep up the good work
Andrew
BTW, I've seen a bonnet with a V8 firing order written on it, & a D7 Cat transmission case with a note saying "I love Leon" written on the inside. Does that count? LOL
I just love watching true craft masters doing their utmost for everything they put their hands on - knowing full well that 99% of people will never notice nor appreciate the effort.
Reminds me of a passage from the fantasy book "Pawn of Prophecy" - part of the Belgariad series by David Eddings - where the blacksmith was asked why he was spending so much time file-finishing part of a wagon hitch that no-one would ever see. He responded that it was because HE knew it was there and that if he didn't do the best that he could, that he would feel ashamed every time it went by.
With this new lease on life, I hope this amp gets enjoyed, cranked and gets its arse played off for the next 50 years.
If anyone complains that you go too far, they're telling you who they are.
Ha! Good point there, mate!
They walk amongst us.
@BradsGuitarGarage I don't think they walk. They more likely jump from tree to tree
Or wander from crack house to crack house.
That green slime is from a poorly made PVC insulation breaking down and creating a slightly acidic goo (oil) & dissolving the copper in the copper conductors into the gooey oil. It is a mostly a copper oxide in a solution of oil and some vestigial plasticizers so it's not really all that conductive, but it is not at all good for soldering, because as it melts it keeps fouling the contacts and the wires. It is NOT flux! It really all needs to go away. I just redid a lovely old rolling scale B&K VTVM that had a moderate case of the green goo blues. Neat meters and they go up to 1500 volts, which my Fluke meters do NOT go beyond 1000 volts without using a high voltage probe. Most of the High volt probes are 40KV. I usually need more like 2KV-4KV, not 40KV. I have an B&K probe that has resistors that you screw into the probe itself, so it does 4.5KV, 9KV, 45KV, 90KV. There is a spring loaded hook on it so you are NOT trying probe 90KV with hands anywhere near the probe or the DUT.
Nice Job Brad! Make everything right your name is on it mate cheers from Melbourne
Seriously enjoy your content, especially the amp repairs! I worked for GEC Marconi on RAF Nimrod boards back in the days.. it so enjoyable to be part of this. Thank You
Love these tear down rebuild videos you do! Nice work!
I enjoyed the sped up bits, but, to be frank, I would rather have non-time lapse because hearing you berate the other techs is my favorite part of your vids. Your saucy Aussie humor is a balm to my irritation at modern man.
I agree! Less speed up and more cursing!
Yeah!! Fight the power!!
What is boring is now having to small talk while finding something mind numbingly interesting to fill the rest of my lunch break in with :)
If you know a tech in Brisbane with a eye for detail like you, please tell.
I got a Princeton and Ac15 needing to be cleaned up and bulletproof proofed.
Cheers
Pete
The furthest north I'm in touch with is Warren Brown @ Brownout Musical Equipment Repair.
He's a bloody legend.
I'll put the feelers out for anyone further north.
@jasinow Hux Electronics (Brissy) is very good. He services all audio electronics incl large format consoles and 2" multitracks (tape machines) so knows his stuff. Very knowledgeable Tech.
Ahhhh, yes! Warren Huck!
How could I forget Warren!?
It must be my old age getting to me and getting all the Warren's confused!
He's a top bloke and he's your man.
Looks like it's time for me to glove up and crawl up my Quad Reverb's ass to make sure I don't see any green slime. Magnificent work.
Shout out to the customer for doing the right thing 😎👊
Choosing the right guy! This amp will sing!
Outstanding workmanship!
Wow!
You’ve managed to both inspire and put me off digging into my ‘73 in equal measure.
Awesome work as usual. 🎸🤘🏻❤️
Go for it! YOU CAN DO IT!
Nice work mate !
That's a lot work, you got have some major patience to deal with this mess.
Mahalo Brad!
Jeez..he's quick!!
Top dollar quick!
Perfection!!!
Ooof that's some work.. well done man
That will be better after you've finished it than when it left the factory.
4:35 Glad to hear those diodes are being replaced. I have an irrational aversion to them.
9:32 Don't take that guy's soldering iron away. Just store it in him, internally. And put it away hot.
14:10 Those boards look great.
Man! Amazing to see all that work go into a Silver Twin. Too bad you only get a Twin Reverb out of the deal. Hey mate! You’re way too loud, but I can’t hear you!
Beautiful work mate.
Thanks mate!
Regarding the carbon between pins 2 and 3, you said that the transformer generates a back EMF due to there being no load on the secondary of the output transformer. That can’t happen as one of the output jacks shorts the secondary out when no load is present, so no back EMF from no speakers. Should the connections to the speakers go open circuit then it’s possible.
I don’t know if you are a fan of Ken Fisher but he was against using high speed diodes. This is what he said in his Trainwreck pages: “We use 1N4007 silicon power diodes which are effective in suppressing spikes at certain frequencies. These will not necessarily prevent spiking on all amps! There is a fast recovery or high speed diode which will suppress higher frequency arcing however these diodes have a very distinct disadvantage as they alter the tone of the amp! They make the amp sound muddy as they bleed off high frequencies from the output transformer! Trainwreck does not use these kinds of diodes because of their effect on the tone.”
I’m certainly not an authority, but I tend to use UF4007’s for rectifiers as opposed to 1N4007. Is there a reason why you favour 1N4007’s?
Why do you assume that the speaker shorting contacts are functional?
Why do you assume that the open load was due to an unplugged speaker output jack and not a speaker or cable failure or misuse?
That's a lot of assumptions.
It's clear there was a flyback event due to the arcing on the socket and the hum balance pot.
With a junction capacitance of less than 30pf, R5000F's used as flyback diodes have no appreciable effect on tone in my experience. Despite a lot of commenters assuming I know fuck all, I have tested and tried these things and come to my own conclusions.
I used UF4007's in this case. They can present a little less rectification noise than 1N4007's, however with proper grounding methods and heater balancing, the latter's effect is negligible, anyhow.
@@BradsGuitarGarage well why do you think is flyback and not moisture in dust. I don’t think anyone can definitely say how it happened. I have come across jacks that didn’t make a good contact, but you haven’t flagged that in your faultfinding so I guess it largely not a problem. This is a combo so it’s unlikely that the user is removing the speaker jack, this is more common on heads and cabs.
I don’t assume that you know bugger all, but I’m curious how you came to the conclusions that you arrived at.
Black charring on an output socket with no evidence of a spill, combined with arc damage on a hum balance pot definitely points to a flyback event. And with the condition of the speaker wires and the performance of the previous tech, I'd find these add to the supporting evidence.
One thing I learned early in this trade is that every possible scenario and some impossible ones regularly occur thanks to musicians and their adventurous nature. Despite how unlikely a logical person may think they would be. It's what keeps this job interesting if not a little stressful. LOL!
I’m about to dive into undoing crap mods on a very similar circuit (73 Vibrosonic). Great timing! That green goo is terrible. Great work as always Brad!
Brad did mention he thought the green goo was from acid leaking from the filter caps, but it couldn’t be from the caps as it is everywhere. Copper will go green when it rusts, though I wonder where the goo comes from?
I don't believe I said that, and I wouldn't have meant to say that at any point.
It's not from caps, it's a reaction between the copper and or tinning of the wire and the degrading plastic leaching it's plasticizer out of the insulative jacket as it decays. Whatever caused it was sorted mid-seventies. It was a problem with home wiring installed between 1965-1975 as well and now that I've researched it, it is a well documented issue.
See ya soon
Doncha wish you could really de-solder that fast? That was a manky one.
Regarding redoing the original boards, would it more more cost effective to simply replace the old boards with new ones. Then you do not have to go through all the work that you are discussing.
Many people have asked this.
We're reusing the parts that we want to and that are in tolerance.
It's not a standard, readily available AB763 eyelet board layout, so a new board would need to be made, which would be more cost and labour.
Once depopulated, it's straightforward to clean and repopulate.
That's the least of it.
The most time consuming part is replacing all the green ooze and melted wiring and referring to notes regarding layout during that process.
@@BradsGuitarGarage I remember one time I had a MV silver face twin on the bench. It had the same wiring and that power tranny was so hot you could cook eggs on it. I replaced all that, removed the master, and changed out all the coupling caps. It ran a lot cooler after that.
Given the effort that you’ve gone to surely making Garolite boards would be the way to go. You wouldn’t have to worry about the fibreboard going conductive ever.
I have an amp on the bench where the board is ridiculously conductive. I have cleaned one side of the board and the empty eyelet that would hold the tone control caps measures 30VDC. The problem I’m now experiencing is the tremolo oscillator bleeding through into the P.I. stage. I have clean the topside of the board and it makes no difference. I think the wax was put on the board to stop the ingression of moisture into the fibreboard, others claim the black pigment in the board is the problem. I find if I lift the components of the P.I. stage off the board the tremolo noise is at an acceptable level. The anti ticking mod didn’t work at all.
You need to get under it and clean the whole thing and it's insulator board too, mate.
Of course others here are bemoaning me having cleaned anything. Yay, the internet.
I'll let you all argue among yourselves. LOL!
@@BradsGuitarGarage I have been through this with my Bandmaster I cleaned both sides of the board with isopropyl and had the boards in an oven at lowish temperature and it didn’t get rid of the conductivity. Just saying sometimes it’s the board.
I confirm that it's non-conductive with a 1500v megger and heat to the area before repopulating the boards.
@@BradsGuitarGarage that’s the way to fly. I have used the power supply of an amp and attached earth and B+ to the board and measured the eyelets for voltage. Will you demonstrate testing the board with the megger in the video?
The early boards didn’t have wax on them. To put wax on the board is an extra cost and building the amp takes longer. I don’t see Fender taking this action unless there was a problem with the fibreboard. I have had my fibreboard in an oven (at work) for days to dry it out and it didn’t work. I’ve cleaned it on two occasions with using the oven trying to get it to be nonconductive.
So the initial issue was reportedly with the unsealed eyelet boards, particularly in the southern states, getting hydrated and conductive over time.
Fender applied the wax and it worked.
But in 30 years time, another side-effect emerged.
During the thermal cycling over decades and decades of use, the wax melts and congeals in the amp as it heats and cools.
Each time it melts, it absorbs atmospheric contaminants such as tobacco smoke, dust, insect droppings, you name it.
And then it congeals, locks that layer in and the cycle repeats until it starts to reach a point where the contaminants will conduct throughout the wax surface.
Cleaning the wax and contaminant layer off and heating and cleaning the board with solvent typically solves the issue or reduces it to a negligible level. The wax layer is no longer thick enough to attract and retain significant amounts of contaminants.
The board is still more or less sealed and protected from moisture due to the ingress of the wax into the fiberboard, however.
But your results may vary due to local factors or things the amp may have experienced.
7:48 he said "do do"-Butthead.
How long did it take to remove the boards from the amp, remove components, clean the boards and replace the components. I can’t help but think the repair is very expensive and possibly approaching the cost of the amp.
I present a quote.
I make sure the customer is aware of the market price of currently available amplifiers of the same model (of unknown condition other than whatever photos are available, I might add).
Then I let them decide.
@@BradsGuitarGarage fair enough, they know what they are getting into.
The silence is deafening man! Make some tunes and put them over the time lapses. Record us some sick Brad riffs!
Yeah yeah I know.
It muted the audio above 1000% increase in speed.
@@BradsGuitarGarage that a Davinci thing?
Premiere elements thing.
I'm working on some ambient & drone synth stuff and some spacy guitar based stuff too.
@@BradsGuitarGarage chop chop then, we wanna hear some brad tunes in the background while you do your magic!
tasty corrosive plasticiser goo
Why do those tube sockets look so crispy like somebody just burnt the c*** out of them with a high wattage soldering iron? Those poor tube sockets didn't have a chance.
Why does that front panel have those huge holes drilled in it for the pots?I've never seen that before... Whoever did it must not have been a real smart Feller, but a fart smeller.
I would host down that entire front panel with brake clean men all of those wires. Were all that green c*** on it? I would just hose it down with brake cleaner and then take compressed air and blow it. Dry that break clean or evaporate into the air. Leaving nothing behind and get all that greasy c*** right off of there in no time.
Where basic safety is concerned there is no above and beyond, just pass or fail. Having watched part 1 and 2 here, I'm honestly shocked that any tech would allow the amp to leave their care in the state it was in. Deeply wrong and unethical.
You should not replace those blue Paktron or blue molded capacitors without evidence that they have gone bad. They tend to be quite stable and most of them are perfectly good and will last additional decades. They're also higher quality than most other caps you can get today.
In fact, it's absolutely ridiculous that you removed ALL the parts as part of your "restoration", even if you are going to put them all back in place. That's simply unnecessary. You're wasting time and labor to no benefit. Replace the electrolytic caps. Check all the coupling caps for leakage and that they're on spec for value. Replace leaky ones and ones that are way off value. Those white 25/25 Mallory are usually WAY off, I've seen them drop to 5 MFD and I've seen them rise past 75 MFD. Leave resistors that are still in spec. Consider that if they have drifted, it may be a cause of the amp's specific "vintage" tone. CC resistors tend to increase in value as they age. When all the resistors in the amp are 20 percent above spec values, you can expect the tone to have changed.,
I did not replace any of the blue moulded caps, they are fantastic and tested good.
If you want to retain a contaminated and conductive (as tested with the megger) eyelet board for your customers, I feel sorry for them.
As for the rest of your unsolicited instructions, be patient and wait for the next episode so you can tell me how wrong I am. I look forward to it.
@Turboy65 Actually this is the correct and best way to do it - aside from replacing the board with better material. There are many workarounds for this problem and after having done a ton of old Fenders, I've seen most of them. Bits of plastic between the boards, rubber grommets, small P2P terminal strips on sensitive components etc etc. These days old Fenders are worth quite a bit so customers will make the investment but doing this repair 20 years ago (yep, this problem was apparently around then) would have been a different scenario. I have a love / hate relationship with old Fenders, they sound great but really are pile of design and constructional crap in many areas.
@@BradsGuitarGarage IF the board has become conductive, I'll agree with your method. I've only encountered that scenario ONCE and in that case, yes, the board got stripped, baked out, and rewaxed. The restoration went quite well.