http://www.sketchup.com/product/newin7.html

heard about this program from a youtube video on diy fx pedals. i've only had about 30 minutes to mess with it so far, but i can see this will be a really handy program to have. figured i'd pass it on.

i'm having some troubles with my ipod, and i keep forgetting to grab the wife's before she leaves. been looking out for a scope too. i found a $60 diy scope kit on amazon. seems dodgy from the reviews. what is a suitable scope's specs for this kind of work? do i really need to go up to or past 100MHz? a book i read suggested 100MHz. so, i've been working on a digital delay pedal project in the mean time. lol hope to have it debugged and some pics up soon.

next time i'll have some results to report.

oh wow! dude thanks! :dbtu:

TP14, (which i'm guessing is C67 + lead to C69?) meter set to 200v DC reading is 37.2 volts. TP15, (C70 - lead to C66?) reading is 37 volts. TP9 is giving me some trouble in locating the points. i've figured out that the fx jack tip is connect to RC2 wire 5, but i cannot determine which cap is C68 due to all the glue. i'm gonna go back and try to trace that down. i'm still having trouble getting the amp to fade out like it was doing. i don't know if i should be happy or mad about that. it's been cooler than normal in the house. maybe that's not helping? the only thing i've done to the amp beside dissamble it and reassemble it 5 times, lol, is reapply solder to the power caps and touch up a grounding pad that had some weak dirty looking solder on it. gonna get back to it. just wanted to update with that while i spend a couple hours deciphering the layout of the pcb. :lmao:

oh yeah thanks enzo for the pdf. that will be great to add to my project log.  :dbtu:
and dr.gonz thanks for sharing the freesound.org link. i've actually been using that site for some time now for samples to add into music ideas. haven't ever used it as a tone generator, but now i have the perfect application for that. 8|

ok i tested TP9 as wire 5 in RC2 to C68 (finally found it) tested for continuitity, got the tone, turned on the amp 0 volts. which i have now figured out is correct. i don't on the, other hand, know how to measure AC Vpp? i tried just switching my meter over to ac, but that gave me nothing. do i need to have the sine wave running throught the amp while i'm testing for that? got the same results on TP10,12, and 13. TP11 shows being coming from the base of Q5. i looked up the pinout and datasheet for the TIP-142 and 147, and went to find the correct lead to trace and discovered there is no Q5 in the board. just an unused slot for one.

aww geez the diodes got me again.  i plugged the ipod into fx return and no noticeable change in volume. 

ok, i had to go back. i'll just say i will remember zeners are the little glass looking diodes from now on. *facepalm i just meant that i tested the bridge rectifiers also. i didn't know if it would matter, but hey there it is, lol. ahem, well the zeners did not have 15v on them, more a up and down range from 0.00 to 0.065 volts?  whaaaaaa? D17, D14, D13, and D23 all did this. D28 and D29 actually that time more like 16.5v.

Quote from: Roly on March 05, 2013, 09:24:11 AM{Nothing ever goes according to plan, and if it does, you've missed something - Murphy's Law Rules, okay?  :lmao: }
HTH

Dude middle name is murphy i swear. lol. :lmao:

i don't think any of the other amps i have, have a fx loop. but i'll check and definately try pairing them up through the loop on the crate. i want a scope bad. i would like the top dog high speed digital scope, but there's no way i can afford one of those, or even a crt scope right now. not much going in the piano moving business. but no use fusing. gotta get this amp working. lol yeah i know the pics are small even expanded. i guess i can try without hd next time. maybe use less space for a sd pic to keep the image size big. yes sir, a couple of diode tests and test points 9, 14, 15. a hunting i will go. 8|

well the marshall mg30fx i have doesn't have a fx loop, but it has a cd in and a emulated line out. which from the idea i'm getting from what you guys have been telling me is that those 2 jacks should be relatively the same. so i tried plugging into the crate's fx return with the marshall in the line out. no difference in volume, but the sound was distorted. i tested the 2 diodes both had 15-16v on them. tested the bridge while i was at it, and they had about 4.5v on them. i'm having trouble locating the test points though. i don't see any marked pads on the top side, and on the bottom i only see 1 or 2 empty pads.

LOL if i didn't already have 6 none working amps i would get one of those 20watt chip amps. i work at a music store moving pianos, but what i want to do is take over the guitar side when our current guy retires. he's a guitar repair tech, and i'm learning what i can from him in that side of my goal. but he know squat about amps past the tubes and transformers and so do i. so i get the warranty repair amps that the company doesn't want us to bother shipping to them. they'll just send a replacement. but i usually don't know where to start. lol

hey guys. i started doing these lessons, and lessons 1&2 weren't to hard to understand. lesson 3 though kinda threw me off. so gonna spend a little more time on it. lol. i have a cool book you guys might be interested in picking up, How to Diagnose and Fix Everything Electronic by Michael Jay Geier. 

oh, lol, i was talking about figuring out how to get the pics posted. i had to resize them to reduce file size. the amp has me thrown for a loop. lol ah geez i can't believe i didn't think of that.  :loco

thanks

hey i figured it out. lol. the 1st pic is of original fx loop jacks. 2nd is of pcb with replaced jacks, the jack without the nut is the speaker extension. 3rd is the power supply side of amp and 4th and 5th pics are a continuing of the 3rd. the 5th has the effects stage with the blue and white braids. the schematics are of amplifier stages. if you guys want the fx stage pages i'll get those up. on the fx board in the 3rd pic there is a grey ribbon cable with a white connector. can someone please tell me how to disconnect those without damaging them? lol 

i tried the loop bypass trick. no change, but a faint hiss. i also tried plugging everything in, and nothing. i took some pics of the amp and schematic i have, but they all take too much memory to post. xP

sorry i've never used the effects loop on any amp. so i don't know alot about it. well with a pedal hooked up in the loop. the sound does not come through. the mention of the crazy noise was created by the delay and hum from the plug, not the actual vibro sound. actually when the fx return jack has a plug in it, it kills all sound. i guess signal was the wrong term to use, lol. though i'm not real sure how to test a jack with a multimeter. what i did was while the amp was on i plugged into that jack, and set my meter to 200v dc since that is the next setting beyond 20v (which i tried as well). and put my leads on the 2 tabs on the jack and got nothing, 0v. i figured there should be some voltage going across the jack when plugged in.

 Well so far I haven't been able to get the amp to fail, besides the quarter volume problem. i had the chassis out of the cabinet at first, so i put everything back together, and still no failure. so i never got the voltages under failure. the 5w resistor tested ok, but was super fricken hot. wow. 5w of dissipation must be alot. lol. i rigged up a cable to hook up an extension speaker, and yes the speaker in the combo did not cut out. also found that there is no signal from the fx return. so went to the jacks. they look good. i sprayed them all with deoxit. no change. hit it with some fresh solder. nothing. i guess i'm gonna have to get under the board to check where the ribbon cable connects. i did have to re solder the power caps because i was being hastey and not methodical. bad moves on my part. won't do that again, i promise. lol. and as far as the tech guy goes. i don't think he took any real time with this amp. there is noone within 50 miles of where i'm at that works on amps. so he gets flooded. why i want to be a amp tech.

*note* i found that with a vibro pedal in the loop, and the amp fx set to delay. even though the return isn't working when i pulled the plug out to where only the sleeve is making contact in the jack. it makes this awesomely wild noise. 

*note2* the amp is not a gfx65, it is a glx 65. sorry about that. i just realized i wrote the wrong amp model.  :duh

Thanks guys.

QuoteLeave them alone.   Why do you think they are the problem?

Quote
I had thought that maybe once the amp warmed up the caps would become leaky and drain out. But thinking about that now that would drain the power from the whole amp, not just the output.

QuoteYou have a jack on the panel for extension speaker?

yes it does. as well as a effects loop.

Quoteb) confirm that you still have main and preamp supply voltages under fault conditions.

gonna check up on all these asap. I had thought about a chip overheating. Since it has been to a tech before it was given to me to learn on. He never found the problem. I thought that might have been easy to overlook? As I said though i know jack by comparison. Will return with results. thanks again.