It fought me to the bitter end! | Vintage Super Reverb Amp Repair - Pt. 4
Рет қаралды 836
Күн бұрын1970's Super Reverb Playlist: • 1970's Super Reverb
00:00 - Doghouse
02:40 - First power on
07:38 - Left a mod in to test
08:38 - Bias attempt #1
09:52 - Bias attempt #2
11:22 - Voltage in the board :(
12:32 - What is going on?!?!?!
15:31 - Lets remove some wax...
16:08 - Testing PI caps for leakiness
18:11 - Bias balance + variable voltages
21:45 - Stability check after all the work
24:37 - BIAS PROBE IS THE WAY
28:03 - Playing test!
31:52 - Weak trem + tick fix
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@roncarter2188 4 ай бұрын
I saw a video where the repair tech had pretty much the same amp and he would lift and remove a section at a time of components and heat the board and remove the wax along with wiping it with alcohol. What a process to do this but it seemed to work out well.
@soapboxearth2 4 ай бұрын
I love adding a 1r at pin 8 of the power tubes to the ground. Then you measure mv across the 1r, and that matches your ma for biasing. Safe and easy. On all my future builds, I'll be adding banana jacks on the chassis for convenience and safety
@YeatzeeGuitar 4 ай бұрын
Yeah I've seen people talk about it, but I've never done it. I try to avoid soldering to the chassis, especially in crowded areas but my new chassis iron is more nimble. Maybe my next order I'll buy some 1ohm's and save for a rainy day. Though I don't really see the value over just biasing with a bias probe. Easier, doesn't require opening the amp up to check/confirm bias is fine. It's just these 70's with the cap from pin 5 to pin 8 to ground that messes it up.
@soapboxearth2 4 ай бұрын
@YeatzeeGuitar on my last build, I ran a wire from each pin 8 to a banana jack mounted on the chassis. 3 banana jacks mounted in a row, with a 1r between jack 1 and 2 and a 1r between jack 2 and three. The middle jack has a wire that runs to a ground lug, and the two end jacks connect to the wires coming off the pin 8 wires. Then, install the bias pot, accessible from the outside of the chassis . Works great. Understandable you.wouldnt do this to a vintage amp, though, lol . My buddy alligator clips a 1r in to do the bias. But the probes works great too
@omarmolina207 3 ай бұрын
Put one probe on the OT CT and the other probe on the plate. This gives you the voltage difference across one leg of the primary without having to subtract. This is your best bet with only 1 volt meter. This eliminates the effect of voltage drift and timing affecting the measurement.
@Lu_Woods 4 ай бұрын
Sounds fantastic!!
@YeatzeeGuitar 4 ай бұрын
It's made me want a super! Sounds so good, 4x10 is a real magic combo. Quite loud and heavy though, very clean until serious volumes. They're so undervalued right now, BF supers are available all day long for sub 2k here so I'm not jumping at anything... but eventually I'll grab one!
@Tonefiend 4 ай бұрын
One of my favorite BF fenders for Les Pauls Fantastic sounding amps. I need to grab one while they’re cheap as well!
@J.C... 4 ай бұрын
13:23 Jeez. I'd be pulling my hair out lol
@YeatzeeGuitar 4 ай бұрын
I definitely was
@nicksregor4208 4 ай бұрын
The weird solder color is indeed from mixing leaded with unleaded solder. Those typically form weak/brittle joints.
@YeatzeeGuitar 4 ай бұрын
Mmm, good to know. Everything I work on is vintage so leaded solder to begin with.
@krisharrop3764 4 ай бұрын
A bad center tap ground on the PT will cause the problem. Ground the direct to chassis like they did in BF panel days. Grounding to the heavy transformer bolts is a common fault.
@YeatzeeGuitar 4 ай бұрын
Interesting! The ground looked solid, I always check those, but if you see the first / second video of this amp's series you'll see the 3 prong ground was on a transformer bolt and it came loose. I did that one directly to the chassis, I guess maybe as common practice I should just convert all of those to chassis grounds going forward
@J.C... 4 ай бұрын
What kind of soldering station do you use? I see blue so I'm guessing a Hakko? I just picked up a new KSGER T12 V3.1s station that's quite a bit better than the Weller station I was using. It's that entry level one that only has a knob with 1-5 and no sensor in the soldering iron for feedback. Soldering was easy before but it's even easier now with this new one. So I was just curious what you use. 🤷👍 This one has tips you can change while hot, which is not something I'm used to lol. Gets to 400* C in 8 seconds. I really like it. It has the tips with the heater built into each tip, I believe.
@YeatzeeGuitar 4 ай бұрын
This guy: www.circuitspecialists.com/60_Watt_Soldering_Station Been rock solid for me, never had an issue and very affordable.
@huddyskiba1 4 ай бұрын
Good deal! 🍻
@roncarter2188 4 ай бұрын
I saw a video where the repair tech had pretty much the same amp and he would lift and remove a section at a time of components and heat the board and remove the wax along with wiping it with alcohol. What a process to do this but it seemed to work out well.
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