11 ай бұрын
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@valleywoodstudio7345 6 ай бұрын
I was given a dead BJ III for free - dead mains transformer and output transformer and a clear burn on the cicuit board for the EL84s - so I got an aftermarket one (much heftier!) alongside replacement transformers. In the UK they are all wired up for EU 230V from the factory when they should be connected up to 240V - the connections are there inside! Considering mains outlets can legally pump up to 256 V you can see how these things could cook. Aside from the bias mod this is an added thing UK peeps should be aware of! Mines running fine now and I like it - only mod has been to implement a switch across the bright cap. Would like to try either the Celestion A or WGS 65 as a speaker swap.
@rlarsen4562 9 ай бұрын
Sounds great.
@rlarsen4562 9 ай бұрын
Has Fender ever commented on the years of design and parts quality reviews like this one ?
@OhmicronIndustries 9 ай бұрын
Well I think there have been some modest improvements over the years, although many are purely cosmetic and they've failed to address the biggest problem which is that the factory bias is disastrously hot. At the end of the day it's a price point amp and I think Fender is probably satisfied with the lifespan of them. There's a planned obsolescence quotient at play I suspect.
@goodun2974 9 ай бұрын
PS, a somewhat unusual circuit, with signal ground lifted above the chassis ground; you hardly ever see that done in tube type guitar amps, although it's fairly common in pro audio gear, to precent ground loops. The way it's drawn out is strange; note that they didn't show heater voltage going to pin 4 of the 12AX7 tubes, only to 5 and 9....and one leg of the high voltage AC secondary feeding the fullwave bridge is shown as "zero volts", which is definitely not true!
@OhmicronIndustries 9 ай бұрын
Yeah, not a particularly complicated circuit but definitely unusual as you stated. There were certainly some inconsistencies in the schematic and several places on the pcb that were unpopulated. I'd have to look at the board again but I wonder if pins 4&5 on the preamp tubes are tied together on the board?
@goodun2974 9 ай бұрын
@@OhmicronIndustries , they would have to be in order to use both halves of the triode. Trace Elliott products were not known for consistency, reliability, or repairability. "Uh-oh, the infamous Trace Elliott bass amp is fucked up again". David Lindley, from an ElRayo-X gig around 1988 (bassist Jorge Calderone was using one). I'm amazed that replacement boards are still available, especially as Trace Elliot has been through several owners/distributors (Ovation, back in the day, IIRC).
@goodun2974 9 ай бұрын
For me, "Eighteen" came and went 47 years ago! Great tune; I love the original Alice Cooper Band. There's a video of them on KZfaq playing "Black Juju" and several other songs from side 2 of "Love It To Death" on a small stage, like a high-school auditorium!
@OhmicronIndustries 9 ай бұрын
Haha...Thanks for sticking with the vid long enough to see my lousy guitar playing. I love Alice Cooper and he still puts on a really great show 'til this day.
@goodun2974 9 ай бұрын
@@OhmicronIndustries , I didn't care for "Welcome to my Nightmare" or anything that came after, but the original ACB was great. By 1979, Alice was getting falling-down drunk before going on stage (there's video on KZfaq). He did get sober eventually but it seems he had to take up golf (ugh 😖) in order to do it, and I don't know which addiction is worse!
@davekeating. 9 ай бұрын
The first question I'd ask is, "Why did amp fry without blowing a fuse?" 'Cos it should have...
@OhmicronIndustries 9 ай бұрын
Agreed. I'll never know for sure but maybe the buyer blew the fuse that it came shipped with (calls for a 1A) and then just replaced it with whatever he had on hand? Total speculation on my part, would love to hear any theories you have.
@davekeating. 9 ай бұрын
@@OhmicronIndustries Increasing the wattage of resistors that burn out is akin to putting in a bigger fuse. The six watt screen resistors, R25 and R26, should be 1W or 2W, flame resistant. Trace Elliot never thought that someone might start upping or bypassing a fuse that keeps blowing - possibly due to a power tube “disturbed’ during transit? R32, the 4W screen dropping resistor fried, also R36, 1/4W resistor, which, according to schematic, is someway related to heater supply? Two 1W screen resistors would have stopped all that nonsense.
@OhmicronIndustries 9 ай бұрын
@@davekeating. I still can't get my head around how that heater circuit cooked. Interestingly, the original R25 & R26 were undamaged. Also of note, the schem lists R32 as 4w while the BOM says 6w. At the time the 10w was what I had but perhaps I should order a more suitable replacement. FWIW the amp has been working properly for at least a year now with no problems.
@user-qm7nw7vd5s 9 ай бұрын
Circuit board mounted tube sockets is a nonstarter. Straight to the trash bin! I would have kept the speaker, and maybe the cabinet (if it’s not particle board). Where was it made?
@OhmicronIndustries 9 ай бұрын
These versions are made in Mexico. Since the tubes mount to a separate PCB, it's not difficult to remove it and just wire up sockets if one is so inclined. Like most production models, there are corners cut to save $ but a lot of people really like the way these sound and I had zero problems selling it.
@tomterrif8503 10 ай бұрын
Clipping one leg of C3 makes the amp sound 100x better. It is another ridiculous Fender flaw, basically a bright switch that's on all the time. Just did it to my amp, and it makes a huge difference.
@OhmicronIndustries 9 ай бұрын
Good info...if I have another one of these come across my bench (which seems pretty likely😅) I will give it a try.
@rlarsen4562 9 ай бұрын
What about for the #1 USA model considered darker sounding than the later models ?
@jaysorensenIBEW 10 ай бұрын
Your video production was good, dude. You did some things I haven't done to my greenboard version. I just did the Fromel mod, CRex, MM OPT, bias set, but not potted. Etc. Right on 🤙
@OhmicronIndustries 9 ай бұрын
Appreciate you checking it out and thanks for the kind words.
@LarsonGuitarPlayer 10 ай бұрын
I would gladly buy this amp knowing it won't fail on me for a long time.
@zbaby82 11 ай бұрын
Nice repair. Fender makes good guitars. But I don't trust their amps.
@John_Galimore 11 ай бұрын
Nice fix. Yeah everybody dogs the construction. But it is a decent sounding little amp. The layout is certainly not as bad as a Mesa. If I ever find a decent amp tech in Eastern North Carolina I'm going to have them firm up the common fail points on my IV. Thanks for the video.
@OhmicronIndustries 11 ай бұрын
Thanks for checking it out. I think adding a variable bias on these can protect against common power section failures... but if you have the money, I would advise replacing the pcb that holds the tubes. They've been known to cause fireworks in the back of the amp occasionally :)
@thorynziemba2813 11 ай бұрын
This guy is a genius!