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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Studiomaster Powerhouse Vision 8 , 700W mixer amp,1996
Didn't think when initially checking out, but what is the "group" slider
function,? no www user manual found. Anyone any schematics for it ? (ps no emails to whatever this posting apparently throughs up) One channel clipping, then dropping out totally after a time, first problem in preamp, imbalanced gain, second unknown pa or prea. At least possible to swap the pa channels over it would seem , to resolve to pa or prea , if nothing actually found. Also what governs the fan startup, comes on at power up for 2 seconds (presumably normal) switches off and comes on whan heated up but nothing obviously separate from the amp/s for temp monitoring or total/channel cutout, ie no relays, so some sort of gain control coming into play to kill the channel. |
#2
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Studiomaster Powerhouse Vision 8 , 700W mixer amp,1996
Meat Plow wrote in message
... On Sat, 8 Aug 2009 07:41:16 +0100, "N_Cook" wrote: Didn't think when initially checking out, but what is the "group" slider function,? no www user manual found. Anyone any schematics for it ? (ps no emails to whatever this posting apparently throughs up) One channel clipping, then dropping out totally after a time, first problem in preamp, imbalanced gain, second unknown pa or prea. At least possible to swap the pa channels over it would seem , to resolve to pa or prea , if nothing actually found. Also what governs the fan startup, comes on at power up for 2 seconds (presumably normal) switches off and comes on whan heated up but nothing obviously separate from the amp/s for temp monitoring or total/channel cutout, ie no relays, so some sort of gain control coming into play to kill the channel. A group slider may refer to the aux buss group. Don't know how the fan is governed but I'll assume it has infinite control like my Studiomaster 700D amp. That probably gets its feedback from a sink monted sensor, unknown where it is driven from. I've never seen that before, a TO220 device trackside under each pa pcb, thermally touching the heatsink. Only 2 pins used, the B-E junction, with 2 isolated traces to the umbilical ribbon the carries the low voltage rails and signal i/p. I wonder what is special in the 2SD1763A used for that purpose. |
#3
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Studiomaster Powerhouse Vision 8 , 700W mixer amp,1996
N_Cook wrote:
Meat Plow wrote in message ... On Sat, 8 Aug 2009 07:41:16 +0100, "N_Cook" wrote: Didn't think when initially checking out, but what is the "group" slider function,? no www user manual found. Anyone any schematics for it ? (ps no emails to whatever this posting apparently throughs up) One channel clipping, then dropping out totally after a time, first problem in preamp, imbalanced gain, second unknown pa or prea. At least possible to swap the pa channels over it would seem , to resolve to pa or prea , if nothing actually found. Also what governs the fan startup, comes on at power up for 2 seconds (presumably normal) switches off and comes on whan heated up but nothing obviously separate from the amp/s for temp monitoring or total/channel cutout, ie no relays, so some sort of gain control coming into play to kill the channel. A group slider may refer to the aux buss group. Don't know how the fan is governed but I'll assume it has infinite control like my Studiomaster 700D amp. That probably gets its feedback from a sink monted sensor, unknown where it is driven from. I've never seen that before, a TO220 device trackside under each pa pcb, thermally touching the heatsink. Only 2 pins used, the B-E junction, with 2 isolated traces to the umbilical ribbon the carries the low voltage rails and signal i/p. I wonder what is special in the 2SD1763A used for that purpose. You need to be talking to Graham Stevenson (Eeyore) I think he designed it. Ron |
#4
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Studiomaster Powerhouse Vision 8 , 700W mixer amp,1996
"Meat Plow" wrote in message ... On Sat, 08 Aug 2009 16:38:30 +0100, Ron wrote: N_Cook wrote: Meat Plow wrote in message ... On Sat, 8 Aug 2009 07:41:16 +0100, "N_Cook" wrote: Didn't think when initially checking out, but what is the "group" slider function,? no www user manual found. Anyone any schematics for it ? (ps no emails to whatever this posting apparently throughs up) One channel clipping, then dropping out totally after a time, first problem in preamp, imbalanced gain, second unknown pa or prea. At least possible to swap the pa channels over it would seem , to resolve to pa or prea , if nothing actually found. Also what governs the fan startup, comes on at power up for 2 seconds (presumably normal) switches off and comes on whan heated up but nothing obviously separate from the amp/s for temp monitoring or total/channel cutout, ie no relays, so some sort of gain control coming into play to kill the channel. A group slider may refer to the aux buss group. Don't know how the fan is governed but I'll assume it has infinite control like my Studiomaster 700D amp. That probably gets its feedback from a sink monted sensor, unknown where it is driven from. I've never seen that before, a TO220 device trackside under each pa pcb, thermally touching the heatsink. Only 2 pins used, the B-E junction, with 2 isolated traces to the umbilical ribbon the carries the low voltage rails and signal i/p. I wonder what is special in the 2SD1763A used for that purpose. You need to be talking to Graham Stevenson (Eeyore) I think he designed it. Ron Yeah don't talk to us lowly nincompoops about something someone else designed. Where's Graham gone lately ? Used to enjoy some of his design insights, and also his tendency to suddenly fly off the handle occasionally !! :-) C'mon Graham - bet you're still lurking - we all luv ya really ... Arfa |
#5
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Studiomaster Powerhouse Vision 8 , 700W mixer amp,1996
Arfa Daily wrote:
"Meat Plow" wrote in message ... On Sat, 08 Aug 2009 16:38:30 +0100, Ron wrote: N_Cook wrote: Meat Plow wrote in message ... On Sat, 8 Aug 2009 07:41:16 +0100, "N_Cook" wrote: Didn't think when initially checking out, but what is the "group" slider function,? no www user manual found. Anyone any schematics for it ? (ps no emails to whatever this posting apparently throughs up) One channel clipping, then dropping out totally after a time, first problem in preamp, imbalanced gain, second unknown pa or prea. At least possible to swap the pa channels over it would seem , to resolve to pa or prea , if nothing actually found. Also what governs the fan startup, comes on at power up for 2 seconds (presumably normal) switches off and comes on whan heated up but nothing obviously separate from the amp/s for temp monitoring or total/channel cutout, ie no relays, so some sort of gain control coming into play to kill the channel. A group slider may refer to the aux buss group. Don't know how the fan is governed but I'll assume it has infinite control like my Studiomaster 700D amp. That probably gets its feedback from a sink monted sensor, unknown where it is driven from. I've never seen that before, a TO220 device trackside under each pa pcb, thermally touching the heatsink. Only 2 pins used, the B-E junction, with 2 isolated traces to the umbilical ribbon the carries the low voltage rails and signal i/p. I wonder what is special in the 2SD1763A used for that purpose. You need to be talking to Graham Stevenson (Eeyore) I think he designed it. Ron Yeah don't talk to us lowly nincompoops about something someone else designed. Where's Graham gone lately ? Used to enjoy some of his design insights, and also his tendency to suddenly fly off the handle occasionally !! :-) C'mon Graham - bet you're still lurking - we all luv ya really ... Arfa Come to think of it, I havent seen him online lately (we sometimes have a yatter in MSN) or in the pro.live-sound group. Hope he`s ok. Ron |
#6
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Studiomaster Powerhouse Vision 8 , 700W mixer amp,1996
On Sat, 08 Aug 2009 13:33:01 -0400, Meat Plow wrote:
Haven't seen him since for a month or so. I think he gets dragged into here via xpost more often than not. He was posting in sci.e.d on the 7th. -- Geo |
#7
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Studiomaster Powerhouse Vision 8 , 700W mixer amp,1996
"Geo" wrote in message news On Sat, 08 Aug 2009 13:33:01 -0400, Meat Plow wrote: Haven't seen him since for a month or so. I think he gets dragged into here via xpost more often than not. He was posting in sci.e.d on the 7th. -- Geo Perhaps he's just got tired of talking to us lowly menders ... You know what these design boys are like ... :-) Come to think of it though, I'm sure I saw a reply from him in one of the threads on here a coupla weeks back. Arfa |
#8
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Studiomaster Powerhouse Vision 8 , 700W mixer amp,1996
Arfa Daily wrote:
"Geo" wrote in message news On Sat, 08 Aug 2009 13:33:01 -0400, Meat Plow wrote: Haven't seen him since for a month or so. I think he gets dragged into here via xpost more often than not. He was posting in sci.e.d on the 7th. -- Geo Perhaps he's just got tired of talking to us lowly menders ... You know what these design boys are like ... :-) Come to think of it though, I'm sure I saw a reply from him in one of the threads on here a coupla weeks back. Arfa You talking about Eye-Snore? I think he was just in a couple of days ago. |
#9
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Studiomaster Powerhouse Vision 8 , 700W mixer amp,1996
On Aug 8, 8:41*am, "N_Cook" wrote:
Didn't think when initially checking out, but what is the "group" slider function,? no www user manual found. Anyone any schematics for it ? (ps no emails to whatever this posting apparently throughs up) One channel clipping, then dropping out totally after a time, first problem in preamp, imbalanced gain, second unknown pa or prea. At least possible to swap the pa channels over it would seem , to resolve to pa or prea , if nothing actually found. Also what governs the fan startup, comes on at power up for 2 seconds (presumably normal) switches off and comes on whan heated up but nothing obviously separate from the amp/s for temp monitoring or total/channel cutout, ie no relays, so some sort of gain control coming into play to kill the channel. glad to see we are not alone got similar problem,have run studiomaster vision 8 for 12months no prob but have suspected fan not doing its stuff. summertime is hot here so used external fan just to be sure,However--- big prob occured running just one guitar in practice session, unit suddenly lost digital display, developed loud squeal from both speakers, master straight to off, peak red lights showing max!! then nothing. tried powering up again same result. have carried out detailed inspection, all pcb's ok visually.ribbon cables and pins good,transformer seems ok but I'm not sure what value outputs I should be measuring at each pin?? would really appreiciate any help |
#10
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Studiomaster Powerhouse Vision 8 , 700W mixer amp,1996
wrote in message
... On Aug 8, 8:41 am, "N_Cook" wrote: Didn't think when initially checking out, but what is the "group" slider function,? no www user manual found. Anyone any schematics for it ? (ps no emails to whatever this posting apparently throughs up) One channel clipping, then dropping out totally after a time, first problem in preamp, imbalanced gain, second unknown pa or prea. At least possible to swap the pa channels over it would seem , to resolve to pa or prea , if nothing actually found. Also what governs the fan startup, comes on at power up for 2 seconds (presumably normal) switches off and comes on whan heated up but nothing obviously separate from the amp/s for temp monitoring or total/channel cutout, ie no relays, so some sort of gain control coming into play to kill the channel. glad to see we are not alone got similar problem,have run studiomaster vision 8 for 12months no prob but have suspected fan not doing its stuff. summertime is hot here so used external fan just to be sure,However--- big prob occured running just one guitar in practice session, unit suddenly lost digital display, developed loud squeal from both speakers, master straight to off, peak red lights showing max!! then nothing. tried powering up again same result. have carried out detailed inspection, all pcb's ok visually.ribbon cables and pins good,transformer seems ok but I'm not sure what value outputs I should be measuring at each pin?? would really appreiciate any help I've not got the schematic but I've found you can run it stripped down. Disconnect the 2 pa and all the ribbon cables except the one between the ps one, via small rear panel and up to the mixer. To check for any mixer problems, removing display and memory stuff, monitor output by phones. It looks, not done so yet, that you can then plug in one amp at a time , or swap around , to localise single channel problem to one ch or the other in pa or mixer section. There seems to be odd power rails , +/65V main power rails and a pair of +/79V. I have some monitored voltages at the pa headers, will get back to it today -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
#11
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Studiomaster Powerhouse Vision 8 , 700W mixer amp,1996
With pa's and mixer removed and Conn3 and conn4 ribbons removed, so just the
main combined ps and thermal board in place, DC voltages on con3 80,0.2(£),15,0,0 -80,16.6($),0,0,0 (*) * has 0.6V ac, and £ has 0.2Vac on it with 400Hz input and 0db bar registered on the meter $, 16.6V via 100R to base of thermal monitor TO220 ,to test point T12 , obviously drops down to Vbe , with pa in place T10 for the other amp TP The 0.6V ac also on that pin of conn4, clear and balanced , unlike originally with all connected, very marked signal imbalance. There was a problem with the "group" slider , but maybe not the cause of original problem. I will next try with swapped pas in place, then display board if all seems well. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
#12
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Studiomaster Powerhouse Vision 8 , 700W mixer amp,1996
Previous 2x5 header volts viewed/monitored at pins , starting from main caps
end At 75 percent or less of mains voltage both red LED "fault" lights light, gives some sort of check of functioning. I don't know what temperature is required to activate the yellow LEDs and channel/channels ? shutdown, but presumably greater than 90 deg c With PAs loose(on nylon standoff only, not nutted down) in the amp , make sure there is insulation between both sets of live heatsinks. You can monitor signal in of the PA at R11 , R9 end. Monitoring output and T12 TP, increasing the heatsink temp with hot air gun and fan off. No change in output level up to 90 deg C. With fan connected , fan comes on (at T12) with Vbe between 0.61 and 0.62 and temp between about 45 and 55 degree C (the "thermal" Tr is underneath), dropping to 0.52 or so at 90 deg C. Both channels checked like this -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
#13
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Studiomaster Powerhouse Vision 8 , 700W mixer amp,1996
Hello to everybody!
I need the user manual for stidomaster powerhouse vision 8 , anybody can help me!? THANKS! |
#14
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Studiomaster Powerhouse Vision 8 , 700W mixer amp,1996
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#15
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Studiomaster Powerhouse Vision 8 , 700W mixer amp,1996
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