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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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Yamaha SPX 90, 1986 , Digital Multi Effects Processor
Been looked at by one supposed repairman and returned in a sorry state.
SMPS problem initially , but now could be more than that. I don't suppose anyone has a schematic for this kit, may not be necessary but just in case. Local recording studio's favoured piece of kit , with no full modern day replacement it would seem -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
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#2
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Yamaha SPX 90, 1986 , Digital Multi Effects Processor
N Cook wrote:
Been looked at by one supposed repairman and returned in a sorry state. SMPS problem initially , but now could be more than that. I don't suppose anyone has a schematic for this kit, may not be necessary but just in case. Local recording studio's favoured piece of kit , with no full modern day replacement it would seem -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ Millions of them made, superseded by the SPX 900. All the programs within also contained in the much more capable REV-7. The 90's and many other Yamaha devices of the mid-80's suffered from a potting compound which often turns conductive with age.... jak |
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#3
Posted to sci.electronics.repair
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Yamaha SPX 90, 1986 , Digital Multi Effects Processor
jakdedert wrote in message
. .. N Cook wrote: Been looked at by one supposed repairman and returned in a sorry state. SMPS problem initially , but now could be more than that. I don't suppose anyone has a schematic for this kit, may not be necessary but just in case. Local recording studio's favoured piece of kit , with no full modern day replacement it would seem -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ Millions of them made, superseded by the SPX 900. All the programs within also contained in the much more capable REV-7. The 90's and many other Yamaha devices of the mid-80's suffered from a potting compound which often turns conductive with age.... jak Cold checking , have found 2 things wrong with the ps so not powered up yet No SMPS controller IC on the ps board , a TOP66 switcher driver and 3 small transistors. Raw + and -18V go to main board +/-15V regulators , raw 5V , ie rectifier off the switching transformer followed by one L and one C goes straight to the 5V TTL rail. Not even an obvious fat 5V zener across it. No SMPS controller IC , that I can see on the main board and the 2 lines from the main board marked PE and PC that go to the mains side of the ps via opto isolator , I'm assuming is go / no-go for the moment. 5V regulation via the whole ps unit ? very strange -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
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#4
Posted to sci.electronics.repair
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Yamaha SPX 90, 1986 , Digital Multi Effects Processor
N Cook wrote in message
... jakdedert wrote in message . .. N Cook wrote: Been looked at by one supposed repairman and returned in a sorry state. SMPS problem initially , but now could be more than that. I don't suppose anyone has a schematic for this kit, may not be necessary but just in case. Local recording studio's favoured piece of kit , with no full modern day replacement it would seem -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ Millions of them made, superseded by the SPX 900. All the programs within also contained in the much more capable REV-7. The 90's and many other Yamaha devices of the mid-80's suffered from a potting compound which often turns conductive with age.... jak Cold checking , have found 2 things wrong with the ps so not powered up yet No SMPS controller IC on the ps board , a TOP66 switcher driver and 3 small transistors. Raw + and -18V go to main board +/-15V regulators , raw 5V , ie rectifier off the switching transformer followed by one L and one C goes straight to the 5V TTL rail. Not even an obvious fat 5V zener across it. No SMPS controller IC , that I can see on the main board and the 2 lines from the main board marked PE and PC that go to the mains side of the ps via opto isolator , I'm assuming is go / no-go for the moment. 5V regulation via the whole ps unit ? very strange -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ There are 15 assorted wirewound resistors on this ps , again rather odd. If I get it working , a ventillation hole and grill cut in the top cover would help. |
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#5
Posted to sci.electronics.repair
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Yamaha SPX 90, 1986 , Digital Multi Effects Processor
N Cook wrote:
N Cook wrote in message ... jakdedert wrote in message . .. N Cook wrote: Been looked at by one supposed repairman and returned in a sorry state. SMPS problem initially , but now could be more than that. I don't suppose anyone has a schematic for this kit, may not be necessary but just in case. Local recording studio's favoured piece of kit , with no full modern day replacement it would seem -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ Millions of them made, superseded by the SPX 900. All the programs within also contained in the much more capable REV-7. The 90's and many other Yamaha devices of the mid-80's suffered from a potting compound which often turns conductive with age.... jak Cold checking , have found 2 things wrong with the ps so not powered up yet No SMPS controller IC on the ps board , a TOP66 switcher driver and 3 small transistors. Raw + and -18V go to main board +/-15V regulators , raw 5V , ie rectifier off the switching transformer followed by one L and one C goes straight to the 5V TTL rail. Not even an obvious fat 5V zener across it. No SMPS controller IC , that I can see on the main board and the 2 lines from the main board marked PE and PC that go to the mains side of the ps via opto isolator , I'm assuming is go / no-go for the moment. 5V regulation via the whole ps unit ? very strange -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ There are 15 assorted wirewound resistors on this ps , again rather odd. If I get it working , a ventillation hole and grill cut in the top cover would help. Shouldn't be needed, those things get racked up in close proximity to other units for years without overheating, they are normally considered extremely reliable even when running 24/7. Although considered a 'classic' in it`s day, there are several modern units which outperform the SPX90 at a far lower price. If you really get stuck and it`s imperative that it gets repaired, drop me a line, I know of a company up here in the North who will definitely sort it out. Ron(UK) -- Lune Valley Audio Public Address Systems Hire Sales Maintenance www.lunevalleyaudio.com |
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#6
Posted to sci.electronics.repair
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Yamaha SPX 90, 1986 , Digital Multi Effects Processor
Ron(UK) wrote in message
... N Cook wrote: N Cook wrote in message ... jakdedert wrote in message . .. N Cook wrote: Shouldn't be needed, those things get racked up in close proximity to other units for years without overheating, they are normally considered extremely reliable even when running 24/7. Although considered a 'classic' in it`s day, there are several modern units which outperform the SPX90 at a far lower price. If you really get stuck and it`s imperative that it gets repaired, drop me a line, I know of a company up here in the North who will definitely sort it out. Ron(UK) -- Lune Valley Audio Public Address Systems Hire Sales Maintenance www.lunevalleyaudio.com It was that hand over period , 80s , when phenolic pcbs went over to polyester. This Yamaha has polyester main board and phenolic light brown ps pcb that has a lot of heat dark browned/brittlised? areas. Not surprising with assorted 15 W/W plus sm driver etc with no ventilation holes anywhere. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
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#7
Posted to sci.electronics.repair
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Yamaha SPX 90, 1986 , Digital Multi Effects Processor
Ron(UK) wrote in message
... N Cook wrote: N Cook wrote in message ... jakdedert wrote in message . .. N Cook wrote: Been looked at by one supposed repairman and returned in a sorry state. SMPS problem initially , but now could be more than that. I don't suppose anyone has a schematic for this kit, may not be necessary but just in case. Local recording studio's favoured piece of kit , with no full modern day replacement it would seem -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ Millions of them made, superseded by the SPX 900. All the programs within also contained in the much more capable REV-7. The 90's and many other Yamaha devices of the mid-80's suffered from a potting compound which often turns conductive with age.... jak Cold checking , have found 2 things wrong with the ps so not powered up yet No SMPS controller IC on the ps board , a TOP66 switcher driver and 3 small transistors. Raw + and -18V go to main board +/-15V regulators , raw 5V , ie rectifier off the switching transformer followed by one L and one C goes straight to the 5V TTL rail. Not even an obvious fat 5V zener across it. No SMPS controller IC , that I can see on the main board and the 2 lines from the main board marked PE and PC that go to the mains side of the ps via opto isolator , I'm assuming is go / no-go for the moment. 5V regulation via the whole ps unit ? very strange -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ There are 15 assorted wirewound resistors on this ps , again rather odd. If I get it working , a ventillation hole and grill cut in the top cover would help. Shouldn't be needed, those things get racked up in close proximity to other units for years without overheating, they are normally considered extremely reliable even when running 24/7. Although considered a 'classic' in it`s day, there are several modern units which outperform the SPX90 at a far lower price. If you really get stuck and it`s imperative that it gets repaired, drop me a line, I know of a company up here in the North who will definitely sort it out. Ron(UK) -- Lune Valley Audio Public Address Systems Hire Sales Maintenance www.lunevalleyaudio.com Got it back to working to its earlier non-working condition before it was seriously mangled by a "repairman". Can now see that the original problem was an 85 dec C electro that did not like being cooked in there. The 5V regulation, unlike the +/-15V, is on the ps itself, in discrete form, consisting of 300mW zener,preset and TO92 transistor. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
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