Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

PA Systems A forum for discussion of all parts of a sound reinforcement or DJ system: loudspeakers, mixers (desks) etc.

Bose 1800 series VI Pro amplifier not turning on & Peavey PVi 3000 no output
Bose 1800 series VI Pro amplifier not turning on & Peavey PVi 3000 no output
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 23rd October 2019, 05:53 PM   #21
StewartH83 is offline StewartH83  England
diyAudio Member
 
Join Date: Jan 2019
Location: Stockport, Greater Manchester
Send a message via MSN to StewartH83
That's interesting, I'll look into the use of the kettle, never heard of doing it that way before.

That pre-made tea sounds terrible, when I used to drink tea I had to have it fresh. I prefer coffee these days, American style haha
  Reply With Quote
Old 9th November 2019, 07:03 PM   #22
StewartH83 is offline StewartH83  England
diyAudio Member
 
Join Date: Jan 2019
Location: Stockport, Greater Manchester
Send a message via MSN to StewartH83
So I now have a DBT.

I tried reflowing the the broken solder joint last time but didn't test it again until I got the tester. I've turned it on now. The bulb lights up bright, goes dim then a bright flash when the relay clicks then remains dim. It don't always flash bright when the relay clicks every time I turn it on.

I tried it through a scrap speaker, sounds clear and well, much better than before, upto just past quarter to on the pot, then distorts again.

I'm planning on ordering some copper foil, redoing the joint completely.

The broken joint is on the regulator heatsink, there's two legs on each heatsink going to the board.

Is it a good idea to link a insulated solid core wire to both legs for a better connection?

Can the regulator still be faulty as I understand they distort if they are faulty? I'll order if its a possibility
Attached Images
File Type: jpg IMG_20191022_145827.jpg (293.1 KB, 37 views)
  Reply With Quote
Old 9th November 2019, 11:31 PM   #23
indianajo is offline indianajo  United States
diyAudio Member
 
indianajo's Avatar
 
Join Date: Jan 2010
Location: Jeffersonville, Indiana USA
I sometimes fix burnt out PCB traces with a length of wire. Signal wire I use solid core 28 ga kevlar (which doesn't burn with my soldering iron). Driver current can to up to 5 amps so I would use 20 or 18 ga for that. I drill a hole through the circuit board next to where I am going to attach to, using a small drill and a pin vise. If the PCB is well supported with nothing fragile behind it I'll use a hand crank Yankee drill. The drill pops through the board and goes down to the chuck usually, so you have to plan for that and that is one reason I don't use an electric drill. Too much possible damage.
Then I push the wire through the hole from the component side, and bend over on top of the trace I am trying to splice. Then I solder the wire to the existing trace.
Same with the other end.
Supported by the board like this, the patch wire doesn't tend to fall off.
I wouldn't randomly replace parts to fix a distortion problem. It could be a bad solder joint, or in the case of a Peavey MMR-875t I'm listening to, the front board has to be tightly screwed to the front panel for the signal to not be distorted. (???) (Hard to diagnose with the front panel off for examination.) Any resistor or cap could have a bad weld inside the case, or even transistors & diodes for that matter.
You need to use a scope or sound probe to determine exactly where the distortion is coming from. A sound probe is an amplifier & speaker, protected against DC voltages and against excessive AC voltages. Useful test amplifiers are old PCAT speakers or somesuch low power speaker/amp. Ahead of a 2 vac (line level) or so amplifier input, I'll put 47k resistors on both signal and return. Ahead of that I'll put .047 uf capacitor 400 v rated or higher. Then across the end of capacitor & signal ground, I put line to line 2.1 v zeners, or red LED's. This clamps the input voltage to 2 vac. Then ahead of the zeners I put a 1 k resistor on signal and return. This limits the current on the zener or LED.
Then I can connect the current protected amp return to speaker ground or RCA ring out, and listen through the sound probe/amp to the music at the test point.
If the unit has a flying speaker ground as Peaveys often do, you have to put a .047 uf cap also in the line from sound probe amp ground to unit under test speaker ground. Ahead of the 2 zener voltage clamps and after the 1k resistor.
I use a couple of insulated alligator clip leads or pamona grabbers to connect the sound probe to UUT(unit under test). Much cheaper than a scope probe which is a minumum $60 to replace if you step on it. Audio isn't supposed to go over 20 khz, and even parasitic oscillation is often a mhz or two, which can pass through insulated wire a couple of feet without much attenuation.
When connecting the probe, expect a big pop as DC voltages are equalized by the caps. But after that you should hear what is going on in your unit under test. Turn listening amp gain down in the beginning then turn up as you decide you're not hearing the music coming in your system. (I use a battery FM radio as signal source, turned down to 2 vac out the earphone jack. You don't need the 7 vac a radio will put out at max volume. )
Then when you find the exact point where the distortion starts, you try pressure with a stick or circuit cool spray or a heat gun to determine exactly which part is causing the distortion.
Happy hunting.
__________________
Dynakit ST70, ST120, PAS2,Hammond H182(2 ea),H112,A100,10-82TC,Peavey CS800S,1.3K, SP2-XT's, T-300 HF Proj's, Steinway console, Herald RA88a mixer, Wurlitzer 4500, 4300

Last edited by indianajo; 9th November 2019 at 11:44 PM.
  Reply With Quote
Old 10th November 2019, 02:49 PM   #24
StewartH83 is offline StewartH83  England
diyAudio Member
 
Join Date: Jan 2019
Location: Stockport, Greater Manchester
Send a message via MSN to StewartH83
Thank you so much for your detailed reply and information as I find it fascinating and really enjoy the sharing of your experiences and knowledge. I can imagine your Peavey front panel distortion dilemma was a nightmare. Are they earth screws that need a tight solid connection? I noticed the two screws on this Peavey PSU board were rusted, cleaned them up as best I could. I also noticed, after I put it back together one of the purple caps connection didn't seem good. With gentle wringing one of the joints seemed to 'click' that I could hear and feel when moving it, I'll reflow that next time I remove the board.

Update on the Bose, the front panel fuse is well blown, I can't remember actually checking it previously yet I'm sure it was checked as it's always the first thing I do. This led me to thinking there may be a problem with the output transistors. Like the last time I checked them in curcuit with a MM I checked for continuaty between collector and emitter I get a numeric reading of the same number on both channels but no beep, not sure if it's the cheap MM I'm using being insensitive though?

On the Peavey I'll order some copper foil later but not sure what to use to cover the foil, I'm guessing some kind of fibreglass, never repaired one fully before, only bodged one by scraping away and soldering across the track on a cracked board. I will link a wire across the legs to ensure solid connection, I was thinking solid core mains cable you use in walls if its OK?

So much appreciated the help, I always re-read replies I get on here as your guidance is superb!
Attached Images
File Type: jpg IMG_20191022_144624.jpg (497.7 KB, 35 views)
File Type: jpg IMG_20191110_124525.jpg (152.7 KB, 34 views)
  Reply With Quote
Old 10th November 2019, 05:58 PM   #25
indianajo is offline indianajo  United States
diyAudio Member
 
indianajo's Avatar
 
Join Date: Jan 2010
Location: Jeffersonville, Indiana USA
Mains cable is typically 14 or 12 ga. suitable for 15 to 20 amp currents. No single transistor can pass more than about 5 amps. Too thick a wire when soldering could cause the traces on the board to melt further. So 18 to 20 ga patch wire over a burned power transistor land is fine. I reallize you buy wire in metric sizes, I'll attempt the conversion: wikipedia says 18 ga is 1.02 mm and 20 ga is .812 mm, so any wire you can buy at the auto supply or home store between those sizes is fine.
28 ga for signal transistor areas is .32 mm. .5 mm or .64 mm wire probably won't burn up the silicon junctions.
The actual reading of the transistor you got with the dvm is important. Beep is for continuity, if resistance is that low the transistor is probably shorted. .450 to .770 v are normal readings for silicon transistor junctions. schottky diodes .250 to .450 .
Should go much higher backwards, but not usually to infinity ---- as other circuit parts will take off current.
__________________
Dynakit ST70, ST120, PAS2,Hammond H182(2 ea),H112,A100,10-82TC,Peavey CS800S,1.3K, SP2-XT's, T-300 HF Proj's, Steinway console, Herald RA88a mixer, Wurlitzer 4500, 4300

Last edited by indianajo; 10th November 2019 at 06:01 PM.
  Reply With Quote
Old 10th November 2019, 09:16 PM   #26
StewartH83 is offline StewartH83  England
diyAudio Member
 
Join Date: Jan 2019
Location: Stockport, Greater Manchester
Send a message via MSN to StewartH83
Great advice again. I'll get some 18 or 20 gauge wire as you advise and makes sense.

I so prefer the American way of categorising wire thickness. So much easier and simple.

The transistors were 509 on one channel and 514 on the other. Can't remember if they were 0.509 etc as I was more interested in them not beeping. I'll check again when the MDL 10A fuses get delivered. With a lot of luck that's all it needs but doubt it very much.

I notice your Peavey is the CS series. Not heard a better amp for driving subs yet than those beasts.
  Reply With Quote
Old 10th November 2019, 11:31 PM   #27
indianajo is offline indianajo  United States
diyAudio Member
 
indianajo's Avatar
 
Join Date: Jan 2010
Location: Jeffersonville, Indiana USA
I don't think my DVM puts a point in front of the reading on "diode" scale either. Those readings are fine forwards.
I love the CS800s, but I bought it damaged and very old.I bought a whole band setup for $1000 including 2 SP2-XT speakers that work great, and a 12 input mixer that's fine. On the CS800s I've fixed the burnt out input resistors (probably 75 W guitar amp plugged in the input jack). I've fixed the burnt out fuse in the switcher supply and the overaged electrolytic cap that shorted out. But it still has a channel volume imbalance, that someday I'll address by changing every e-cap, plus whatever else? Was very good sounding, just uneven. Meantime I need about 70 w/ch in my music room, and 400 w/ch is overkill. Meanwhile bought a Peavey PV-4c "for parts or repair" for $28 including freight. $20 in output transistors & $28 in rail caps put it back in service, runs 2-3 hours a day in my TV room, replacing the Samsung "sound bar" that I didn't buy. Those 32" flat screen TV's sound awful.
Got salvage Toshiba 6" projection TV drivers in Newark boxes with a reflex port in the back on the PV-4c, sounds very decent on the PBS concerts.
__________________
Dynakit ST70, ST120, PAS2,Hammond H182(2 ea),H112,A100,10-82TC,Peavey CS800S,1.3K, SP2-XT's, T-300 HF Proj's, Steinway console, Herald RA88a mixer, Wurlitzer 4500, 4300
  Reply With Quote
Old 11th November 2019, 12:15 AM   #28
StewartH83 is offline StewartH83  England
diyAudio Member
 
Join Date: Jan 2019
Location: Stockport, Greater Manchester
Send a message via MSN to StewartH83
Wow, that is overkill for your house, surprised the house hasn't moved down the block haha. You appear to quite enjoy buying broken gear and fixing it up and seems great when your as knowledgeable as yourself.

I have a few QSC and a couple of Crown out on hire, been running for years with no issues. I do go to their location and remove the dust on them all every six months though, take out the fans and clean them with distilled water. I have a soft spot for QSC and older Crown, Yamaha dual monos and Peavey Cs amps.

I got a bargain a couple of weeks ago. I had a Pioneer A-333 hifi amp for sale that I bought filthy for 30, cleaned it inside and changed a few worn caps and resistors and was offered 40 and a Crown XLS 402 too. I don't like it too much but couldn't turn the offer down.

The guy was a retired DJ, said he barely used it over the two years since he bought it. There wasn't too much dust in it so believable. Works fine, just missing volume knobs and power button, I had some knobs about spare so just need to find a button.

I was going to post if there's any improvement I can make to it. Thinking better heatsink on output transistors and possibility of adding a heatsink to bridge rectifier. Increasing the x4 3,300uF caps to x2 6,800uF or x 4 4700uF?

I'll be using it at home running some 250w rms speakers with 2 10" midwoofers per channel. The amp is allegedly 300w per channel at 8 ohms, I doubt that, I don't need more power but do like to keep it as cool as possible.

Interesting to hear your opinion please
Attached Images
File Type: jpg IMG_20191019_185213.jpg (485.3 KB, 27 views)
  Reply With Quote
Old 11th November 2019, 03:02 AM   #29
indianajo is offline indianajo  United States
diyAudio Member
 
indianajo's Avatar
 
Join Date: Jan 2010
Location: Jeffersonville, Indiana USA
The PV-4C had 3 previous sets of output transistors installed before I put the 4th set in. 3 sets of initials on the heat sink? So I had some idea that heat sinking was not adequate?
I added as many of these flattish heat sinks as I could fit in, https://www.newark.com/aavid-thermal...ink/dp/18M8222
Only I used TO-3 ones I had around. aavid-thermolloy 506007b00000g which I paid $.88 each for years ago. Lots of fins.
Digikey has something similar now: 506007B00000G Aavid, Thermal Division of Boyd Corporation | Fans, Thermal Management | DigiKey
I drilled & tapped the heat sinks for #4 US machine screw, added compound and screwed them down.
I then tied bulk filter material over the fan grill, to prevent buildup of dust balls.
I also changed the shutoff snap action thermostat from 100 C to 70 C. I had that laying around too.
That one still runs the fan on high sometimes @ 2 W/ch in my TV room. I might install solder terminal strips to read the emitter current idle bias someday. I used MJ21193/4 and the OEM was MJ15024/25. If that changed the idle current I'll be sorry. Don't leave them on very long, 4 hours max some nights.
Might have just been a case of performers tripping over the speaker cables and pulling the 1/4 phone plugs out over & over, but you'd think a band would move on to dual banana plugs for speakers after the first or second time blowing the output transistors. Maybe they don't read forums.
The bridge rectifier had no initials by it so I didn't worry about it.
Peavey seems to get rated power out of 3300 uf rail caps so I didn't upgrade. If your going to double caps, it seems to me you need to put a cl101 or some NTCR in series with the primary of the transformer to keep the room lights on at turn-on.
__________________
Dynakit ST70, ST120, PAS2,Hammond H182(2 ea),H112,A100,10-82TC,Peavey CS800S,1.3K, SP2-XT's, T-300 HF Proj's, Steinway console, Herald RA88a mixer, Wurlitzer 4500, 4300

Last edited by indianajo; 11th November 2019 at 03:18 AM.
  Reply With Quote
Old 13th November 2019, 06:52 PM   #30
StewartH83 is offline StewartH83  England
diyAudio Member
 
Join Date: Jan 2019
Location: Stockport, Greater Manchester
Send a message via MSN to StewartH83
Sorry for the late reply, been busy with my daughter and teenage drama... The joys haha

Very interesting mods you did there, impressive. It sounds like you improved the temperatures. I see what you mean with bands not being bothered about their gear, as long as it plays that's all they bother about, not everyone but a lot. Bare speaker wire touching chassis is so common, my brother does it with the Peavey but there's no telling him and hates advice. It has speakon connections FGS, he didn't know the plastic stoppers come out for banana plugs connections but I doubt he will do that. I'll just put 3300uF quality caps in my Crown to replace my hated unreliable Jamicon.

I've made some progress on both amps, seems similar issues.

Bose amp:
Fuses were delivered, now powers on into protection mode. When sequence button is switched on (down) when powered up the dim bulb is very bright, the fan kicks in yet no relays click, they buzz quite loud as well as the transformer. Still unsure how to check output transistors with the DMM as I get no beeps. When sequence switch is up on turn on then pushed down no fan kicks in and dim bulb isn't as bright.

Peavey amp:
I only checked one channel through the speaker. The distorted one. Turns out the other channel is dead. After I tapped the output relay on that channel it started buzzing. I took the channel out and a wire with a spade terminal pulled straight out of the board with its pins left in the spade. So that needs resoldering back in. One of the transistors screws were totally rounded off, like one on the front panel and two on the psu board, does my head if someone didn't use the correct sized screwdriver or just used a drill. Anyway I was wondering if the bad spade connection on the dead channel is something to do with the buzzing relay or is the relay faulty?

Last edited by StewartH83; 13th November 2019 at 06:58 PM.
  Reply With Quote

Reply


Bose 1800 series VI Pro amplifier not turning on & Peavey PVi 3000 no outputHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Bose acoustimass 25 series ii internal amplifier Jimbobtx3 Solid State 4 4th March 2019 03:21 AM
Bias Adjustment on Bose 1800 Amplifier jamesdean Solid State 0 18th December 2011 03:45 PM
BOSE 1800 Two series power amp stera66 Solid State 0 15th February 2010 05:19 PM
i have a bose 1800 series 2 workstation amplifier worth???? homertooties Solid State 4 21st September 2008 04:40 PM


New To Site? Need Help?

All times are GMT. The time now is 02:32 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki