BGW750C Power Amplifier Intermittant Sound

This is a big brute of an amplifier

[@gearsbetweenears]

Just got one. Watching you navigate through this will help me immensely. Thanks!

[@djfrank59]

This is an earlier version of the 750C with the T03 case outputs. The later version uses flat packs. The relay board is usually not problematic on these, but still, bad solder joints do exist from time to time. I used to be a warranty station for BGW in New Jersey. Rarely broke down. I still have one in my stereo system. Best sounding solid state amplifier I've ever heard. :) Grab one if you can; you'll be a happy camper.

[@12voltvids]

I wouldn't kick one out of my system.

[@stefanmarinescu5086]

Excelent! Highly enjoyed (as always) your methodical approach.

[@MrChrisRP]

Alright! Power amplifier and power supply videos are my favorite of yours! Time to rock! Just yesterday, I learned a bit about TO-3 package because they are in my STR-7045 and they interest me a lot. I see in the service manual they are mounted with mica insulators. Sony OEM units.

[@jeffadams5510]

Oh I have a PILE of these in various states of disrepair. They are akin to the peavey cs 800 only class AB vs stacked N channel and as I've been told sound WAY better. Nice design!!!!

[@FoulOwl2112]

Lol!! Just looking at a BGW power amp triggers my PTSD and phantom spots before my eyes. This jackleg production company l got my start with used to have a couple of roadcase/rolling racks with 4 or 5 old BGW Performance Series power amps and a over-the-hill, skin-of-its-teeth Furman in 'em. Damn things were already overheating before we could unlock the wheels and roll em off the trailer and plug em in! We'd have to take squirrel cage fans and rig cardboard ducting to the back of the roadcases to keep em from shutting down. One day one of em finally went tits-up for good it seemed. I was pokin around the back of the cabinet (trying to look like l gave a damn) was sniffing around to make sure l didnt smell any real smoke... The moment l stuk my nose right up to it...SHAZAMMM!!!! Damn thing went up like the grand finale on the 4th of July! It's probably the closest I've ever come to literally shittin myself 😆. I was still seein spots before my eyes 9hrs later layin in bed in the Motel 6

[@jasonthewiczman5442]

I Remember this Ampllifer abd video Great Job

[@Natures_Intentions]

That sure is one kick ass amp great repair

[@ricfair9919]

Nice repair! Got to the bottom of this intermittent issue.

[@gavincurtis]

You need Ave's "tappity tap tap" on that relay for proper certification.

[@williamsquires3070]

Yeah, it’d be certifiably… broken! 🤣

[@GuruLaJ]

Awesome vid

[@ny9h]

Brian Gary Wachner told me back in the 80s, his design was different than many esp the Crown DC300. BGW paid much attention to the SOA safe operating area of the output devices, hence so many output transistors. I sold his amps into the marketplace where guys were blowing up speakers , when the devices clipped...or blew taking the rails into the expensive JBL speakers. JBL were not warrantee covered for blowing then up. bill ex JBL & BGW rep in illinois (1980s )

[@annierenard5954]

good video and the first without your watch !!!!!

[@kiefaddict8143]

Great video cutie had an issue with something similar recently.

[@zx8401ztv]

Well done, the monster is back :-D Fixed once and for all, A long weight sticking out of the pcb with leverage focused on the solder. I have always liked transistors for outputs, And linear power supply outputs as well. Just my era of electronics i suppose. Also 4000 series cmos logic and 74lsxx i always liked :-D

[@BoB4jjjjs]

I don't think you went that far into it last time? You did some tests and it fired up. I would need to watch back again!

[@12voltvids]

Last time I was into this unit it started working as soon as I got into it and would not fault again customer took it it ran for months before it faulted.

[@CotyRiddle]

I wished they still built them like this.

[@12voltvids]

They do! The new dynaco and haffler brands are made in Canada and are built like tanks. You pay for quality.

[@marka1986]

@@12voltvids cool. They didn't go to switching power supply and surface mount parts?

[@zulumax1]

So what was the cause of the failure? Thermal cycling due to heat most likely? I watched you video on the Panasonic PV-420D camcorder, mine still works too. Still got one original Panasonic battery and two Radio Shack lead acid batteries. Will have to watch the video on that again to see if I can get some distilled water in them.I was going to recycle them. There is a lot of video jitter on that camera, never really noticed it until you mentioned it, now I can't stop seeing it.

[@MrChrisRP]

Nice Bach at the end! hahaha I actually know what it is from. The best guitar book ever. Speed Lead by Troy Stetina. "#178 Prelude in D, by Johann Sebastian Bach" If not, it sounds very close in my head to it. Man, that book can take even the most atrocious players' skills to the roof. Highly recommend. Awesome fix! Congrats!

[@12voltvids]

Well that track is actually jack waldenmaier (musicbakery productions). May be close or influenced by bach but it is original music.

[@MrChrisRP]

@@12voltvids It is Prelude in D, heh heh. :) kzbin.info/www/bejne/iqfXdK2Vbbabp9k

[@12voltvids]

@@MrChrisRP it is pretty close. The bridge is slightly different as is the tempo it is played.

[@MrChrisRP]

@@12voltvids It's difficult to tell exactly because it is through mic and customer's amp and your speakers, but I think even the time modulated effects (like chorus and the like) are even similar. Could possibly even be a time stretch from one to other. In any case, that amp seems silly great even from here.

[@madpom2]

What is the name of music close to end of video called please

[@12voltvids]

musicbakery.com/baroque-guitar/ This is an adaption of J S Bach BWV1007 Prelude in D

[@jiayihchoo9482]

Did anyone got experience bgw power output burn in several second although voltage bias ok

[@user-xm6qb5cg4i]

RCA 2N3055 2N2955 ?

[@marka1986]

No need something alot better than that lol. Maybe mj15024 mj15025 for replacements

[@b.powell3480]

Replace the relays !? Maybe they are funky!

[@12voltvids]

No broken solder on bottom. Couldn't you see it?

[@b.powell3480]

@@12voltvids Yeah, when you turned the board over, then I could see the bad solder connections! Great video, hopefully the amp will play for many more years!

[@kyoudaiken]

Some people may get triggered again cause he puts on so much solder onto the cracked solder connections. It's just a habit as a repairman that comes from dealing with lead-free solder bull**. You automatically flood it with leaded solder to change the alloy to be much more durable than that lead-free planned obsolescence crap. But on a unit of this age, they probably were still using leaded solder. The thermal stress in those devices, especially when turned on and off, especially where the fan is turned on and off and between 2 speeds is immense, so even leaded solder can crack over time. As you can see the manufacturer of course also didn't put that much solder on in the first place.

[@12voltvids]

The manufacture didn't put that much on because they wave soldered. The board is dipped in molten solder. It has nothing to do with flooding the joint, it is making a good permanent bond. Anyone that has been in the business understands this. The amateurs don't.

[@nickbenke3306]

I had an amplifier recently that had the power relay clicking at high speed - so obviously not powering the unit up! I tested 3 capacitors that were parallel with the relay trigger voltage and they were fried! I'm guessing that they were some kind of smoothing? It worked great with new ones. Good job on fixing the amp, I do enjoy your vids! I emailed you through here a while back, it was titled Logic Loop and a short thesis that I had written about a recurring issue with digital electronics. Did you get it?

[@kurtzembower9297]

Canada that's the birth place of NAD I have also 2 channel vintage NAD conponnates from the early 80's along with my McIntosh units..note there not hooked up together but there nice to hold on to that's all I'm saying.

[@12voltvids]

NAD, new audio dynamics was founded in London England. They were acquired by the Lenbrook group in Canada whom also make LSB speakers. They design and manufacture here in Canada as well as overseas. Many pieces were made by Rotel for NAD. I have a really nice sounding NAD receiver in my bedroom into a pair of psb speakers.

[@jiayihchoo9482]

Hi Fri did u got WhatsApp, I am 20year in repair power amp , only this problem can't solve..Pls help to chat