ounvme Posted June 27, 2011 Share Posted June 27, 2011 I am sure this is an all to common problem with alot of powered subs. I have repaired a few sets of promedia subs and usually they follow the same trend as well. When these amps wont power on 9 out of 10 times its power supply related. The resistors are heavily loaded and run hot, same with the mosfets. When blowing fuses or not getting power into the sub, I always do 3 things. (1) Check the diodes. (2) Check the resistors. (3) Check the mosfets. Usually one of these will be blown or bad causing all the problems. When testing my RW-10 I found that Q402 which is an IRF740 mosfet was fully shorted. This was causing my sub to blow fuses and not have power. $6 later I replaced both Q402 and Q401 and the sub is singing happily again. I am going to list the values of the parts that would most likley blow and the values here for future refrence. The smaller resistors showed no sign of heating or wear and all the color bands were clearly visible so I left those un-measured. Q401 - IRF740 Q402 - IRF740 Q200 - IRF540 D200 - MUR1520 R203 - .1 5% 3W R210 - .1 5% 3W R204 - .1 5% 3W R206 - 100 5% 2W UNREADABLE DIDNT WANNA LIFT FROM BOARD 2W (1) 470 5% by C414 (3) 10 5% Quote Link to comment Share on other sites More sharing options...
Groomlakearea51 Posted June 28, 2011 Share Posted June 28, 2011 Great information!!! [Y] Quote Link to comment Share on other sites More sharing options...
ounvme Posted July 2, 2011 Author Share Posted July 2, 2011 Well unfortunatley the power supply in the sub took a turn for the worse again. I don't really know what happened but the outer IRF740 blew again and one of the diodes on the board behind the mosfets fried. I am thinking it could be the dreaded death of the SMPS transformer. I did find something fairly interesting. There is an error in the silk screen on the little control board. See the picture below. D11 is double marked. I am pretty sure that both diodes are IN4148 types but would like verification of type and the correct direction of D11 Quote Link to comment Share on other sites More sharing options...
ounvme Posted July 2, 2011 Author Share Posted July 2, 2011 I also removed the main transformer to check for shorts. Pin 1 is marked by the white dot on the side. Pin 1 has a wire connected but does not seem to make a connection to any other pin. Pins (2 3 4) & (5 6 7) measure connected. This is the input side of the transformer. On the output side Pins (8 9) (10 11 12) (13 14). Transformer pins up 7-o o-14 6-o o-13 5-o o-12 4-o o-11 3-o o-10 2-o o-9 1-o o-8 It appears that some of the windings are center tapped but I think something is wrong since pin 1 reads no connection to any other pin. The input side of the transformer may be cooked. If someone can also verify that. I may try to rewind it if its shot. Quote Link to comment Share on other sites More sharing options...
TEXASKLIPSCH Posted July 2, 2011 Share Posted July 2, 2011 I don't know if the RW-10 is the same as the SUB-10, but the transformer looks to be the same with the same amount of pins. If I measure between pins 1 & 2, it reads an open. All other pins look to be ok on the input side. The output side looks to be all good as well. Prior to me replacing, 2 MOSFETS before the input side of the transformer, a Thymistor right after the full wave bride rectifer, and a 200V 470uf cap, which is next to the transformer, all it would do is blow fuses. Now I can apply 120V, and it won't pop a fuse, but it won't power the amp circuit either. I'm reading a 165V next to that 470uf 200v cap next to the transformer, but no lower voltages after that.. I think I should be seeing around 60VAC on the output side of the transformer before it's switched to DC and then sent to the Power Amp MOSFETS.. The top of the transformer has the following: indigo 500126 Rev B / TWI 881692 B 0739. I can't seem to track down any kind of matching part #.. I want this fixed!! and I'll fix it if I can replace all the blown parts.. That's if I can find all of the... Else I wonder if Klipsch will fix it.. Appears to be a bad amp design.. Quote Link to comment Share on other sites More sharing options...
ounvme Posted July 4, 2011 Author Share Posted July 4, 2011 Chances are that the transformer is OK. After taking mine apart all the wires seemed to be in good condition. I did take data on all the windings so hopefully I can wind a replacement. I shouldn't have taken it apart but now I know for sure that was not the problem. Pin 1 does not have any connection it is connected to a copper strip in the middle of the transformer and most likley some sort of feedback to the control circuit. I was in the same boat being able to apply power but no output. If possible can you check those diodes on the breakout board for me? Quote Link to comment Share on other sites More sharing options...
ounvme Posted July 4, 2011 Author Share Posted July 4, 2011 I am also pretty sure that the power to this sub stays in a standby mode until a signal is sent to the ribbon cable. That switch on the back that goes between auto/on im sure is somehow tied in with the power supply. For now I am going to try to make a complete schematic of the power supply and figure out how this thing actually works. It may help with figuring out why the fets are blowing and why it will not power on. The ribbon cable has a voltage output for the opamps that power the crossover so we should be getting voltages there too in the 12-15v range. Quote Link to comment Share on other sites More sharing options...
ounvme Posted July 4, 2011 Author Share Posted July 4, 2011 After some close inspection I also noticed this. R400 has a nice crack on both sides. I havent seen a radial resistor like this and can't find any info on the value of it. DSP 104 doesn't return anything relevant when searched. It measures 15ohms but I am assuming that is not correct since the component is cracked. Have a look... Quote Link to comment Share on other sites More sharing options...
TEXASKLIPSCH Posted July 4, 2011 Share Posted July 4, 2011 if you are referring to that green component and it's after a full wave rectifier to the right, then I think that's a thermistor. I couldn't track it down to anything, but noticed it had a TH3 printed on the circuit board right where it was standing. I replaced it with one that I believe was as close of a match as I could find. If the transformer isn't bad, then it's definitely something on the logic side that's preventing the amp from fulling powering on.. there's a 3 wire ribbon that plugs into a socket that's on the board that has the toggle switches and gain control. It's the power indicator LED at the front of the SUB10. I believe the most voltage I've seen out of one of the pins is about 1.5vdc. I think I need about 3vdc to power the LED. I'm getting power, but I'm missing some kind of switching voltage that turns the whole thing on. Pin 1 on the transformer seems to be tied to the drain of one of the IRF740 Mosfets. It's probably something simple and I've overlooked it.. a bad resistor or something that's keeping the whole thing turned off. It's not blowing fushes and I'm seeing 165VDC next to that large cap that's next to T1. Quote Link to comment Share on other sites More sharing options...
ounvme Posted July 5, 2011 Author Share Posted July 5, 2011 I am refering to the green thing. Yes it could be a thermistor. I'll have to try and find out what kind it is and see if i can find the origional value. Quote Link to comment Share on other sites More sharing options...
ounvme Posted July 12, 2011 Author Share Posted July 12, 2011 I have decided to make a full schematic and layout of this power supply and see if maybe I can build myself a replacement. It is more fun to me to design and create something vs shelling out cash for something that will break in a year anyways. I am sure this good info to have saved somewhere anyways seeing as Klipsch is stingy with schematics for us DIY types.[:@] I started with the PDC board 660038RA. R1 - 200KR2 - 1KR3 - 392R4 - 750R5 - 750R6 - 392R7 - 750R8 - 750R9 - 200KR10 - 200K(4/5) (7/8) (9/10) are in parallel to obtain desired values. C1 - R1C 472 KCS 605 (4700pF 60V 5% ????? )C2 - 3300pF 5% 100VC3 - 3300pF 5% 100V D1 - 1N3070D2 - 1N3070D3 - 1N5245BD4 - 1N5245BD5 - 1N4148D6 - DIAC (UNKNOWN VALUE) Q1 - MPS A92 Quote Link to comment Share on other sites More sharing options...
CGodbout Posted October 23, 2011 Share Posted October 23, 2011 D11 is a diac... will work in any way Quote Link to comment Share on other sites More sharing options...
CGodbout Posted October 23, 2011 Share Posted October 23, 2011 The green thing is an inrush current limiter. To check it you have to put a load on it (1 amp) and check if the voltage across its pins go down. It's purpose is to protect the circuit from high peak current at startup, once circuit started it goes near short. Quote Link to comment Share on other sites More sharing options...
TamasM Posted October 25, 2011 Share Posted October 25, 2011 The diac type is DB6. Quote Link to comment Share on other sites More sharing options...
Richard Lukso Posted November 24, 2012 Share Posted November 24, 2012 Wonder if you ever made the schematic. I am fighting a fuse blowing problem on my RW-10 and dont know what resistor values of some are. Quote Link to comment Share on other sites More sharing options...
Fast1 Posted October 10, 2018 Share Posted October 10, 2018 Dragging this one up from the past! Is anyone still working on these by chance? I have questions about the D11 diac. There is other data that supports this devices as a DB4, not a DB6. Can someone clarify how this value was validated? I have this exact daughter board. Quote Link to comment Share on other sites More sharing options...
AlexZander Posted April 11, 2019 Share Posted April 11, 2019 For those who still have the same problem with this, here what fixes mine after I tried to replace and blown few times one of the IRF740. I replaced C2 and C3 then D11 with NTE6412 from Frys electronics. I think the main cause of the problem was the D11. It just hard to tell because you can't test it with ohmmeter. Hopefully this is common to others as well and be able to help. Quote Link to comment Share on other sites More sharing options...
tepot Posted December 6, 2020 Share Posted December 6, 2020 Which of these mosfets would be the best replacement? Mine too are blown. Image: Check All: Mouser Part #: 844-IRF740PBF 844-IRF740APBF 78-IRF740BPBF 844-IRF740LCPBF 78-IRF740LCPBF-BE3 Mfr.'s Part #: IRF740PBF IRF740APBF IRF740BPBF IRF740LCPBF IRF740LCPBF-BE3 Manufacturer: Vishay Vishay Vishay Vishay Vishay Description: MOSFET 400V N-CH HEXFET MOSFET 400V N-CH HEXFET MOSFET 400V 600mOhm@10V 10A N-Ch D-SRS MOSFET 400V N-CH HEXFET MOSFET 400V N-CH HEXFET Lifecycle: - - - - New Product Datasheet: Datasheet Datasheet Datasheet Datasheet Datasheet RoHS: Details Details Details Details Details Specifications Configuration: Single Single Single Single Single Height: 15.49 mm - - - - Length: 10.41 mm - - - - Package / Case: TO-220-3 TO-220-3 TO-220-3 TO-220-3 TO-220AB-3 Packaging: Tube Tube Tube Tube Tube Series: IRF IRF IRF IRF IRF Technology: Si Si Si Si Si Transistor Type: 1 N-Channel 1 N-Channel 1 N-Channel - - Width: 4.7 mm - - - - Brand: Vishay Semiconductors Vishay Semiconductors Vishay Semiconductors Vishay Semiconductors Vishay / Siliconix Forward Transconductance - Min: 5.8 S 4.9 S 2.7 S - - Mounting Style: Through Hole Through Hole Through Hole Through Hole Through Hole Number of Channels: 1 Channel 1 Channel 1 Channel 1 Channel 1 Channel Transistor Polarity: N-Channel N-Channel N-Channel N-Channel N-Channel Channel Mode: Enhancement Enhancement Enhancement Enhancement Enhancement Fall Time: 24 ns 22 ns 14 ns - 20 ns Id - Continuous Drain Current: 10 A 10 A 10 A 10 A 10 A Maximum Operating Temperature: + 150 C + 150 C + 150 C + 150 C + 150 C Minimum Operating Temperature: - 55 C - 55 C - 55 C - 55 C - 55 C Pd - Power Dissipation: 125 W 125 W 147 W 125 W 125 W Product Type: MOSFET MOSFET MOSFET MOSFET MOSFET Qg - Gate Charge: 63 nC 36 nC 15 nC 39 nC 30 nC Rds On - Drain-Source Resistance: 550 mOhms 550 mOhms 600 mOhms 550 mOhms 550 mOhms Rise Time: 27 ns 35 ns 18 ns - 31 ns Standard Pack Qty: 1000 1000 50 50 1000 Subcategory: MOSFETs MOSFETs MOSFETs MOSFETs MOSFETs Typical Turn-Off Delay Time: 50 ns 24 ns 18 ns - 25 ns Typical Turn-On Delay Time: 14 ns 10 ns 12 ns - 11 ns Vds - Drain-Source Breakdown Voltage: 400 V 400 V 400 V 400 V 400 V Vgs - Gate-Source Voltage: - 20 V, + 20 V - 30 V, + 30 V - 20 V, + 20 V - 30 V, + 30 V - 30 V, + 30 V Vgs th - Gate-Source Threshold Voltage: 2 V 2 V 3 V 2 V 4 V Part # Aliases: SIHF740-E3 Ordering Information Stock: 2,355 Can Ship Immediately, 403 Can Ship Immediately, 175 Can Ship Immediately, 196 Can Ship Immediately, 0 On Order: 0 1000 View Delivery Dates 0 1000 View Delivery Dates 1000 View Delivery Dates Factory Lead-Time: 14 Weeks 19 Weeks 10 Weeks 10 Weeks 18 Weeks Pricing: 1: $1.62 10: $1.10 100: $1.05 1: $1.53 10: $1.20 100: $1.15 2,500: $1.10 5,000: $1.05 1: $1.42 10: $1.21 100: $0.898 500: $0.765 1,000: $0.623 2,500: $0.604 5,000: $0.533 25,000: Quote 1: $2.89 10: $2.46 100: $1.96 250: $1.90 500: $1.74 1,000: $1.49 2,500: $1.44 5,000: $1.31 1: $2.88 10: $2.53 100: $1.99 250: $1.93 500: $1.64 1,000: $1.50 2,000: $1.45 5,000: $1.40 10,000: Quote Quote Link to comment Share on other sites More sharing options...
cappytheclown Posted March 24, 2023 Share Posted March 24, 2023 (edited) Hello I have a kilpsch sub 10 subwoofer and it looks like J3 on the board is all brunt up not sure where I would get a new one. Any help would be appreciated I bought this sub off someone on Facebook and it doesn't power on just keeps blowing fuses. I took it apart and saw that the little circutboard comming off of J3 on the mainboard is chard and looking inside it looks like they spilled something on it. everything else looks good but there is one spot scorched like I said. Any help would be appreciated I know how to sodder just never messed with speaker power supplies before. Edited March 24, 2023 by cappytheclown Pics and changed hell to hello Quote Link to comment Share on other sites More sharing options...
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