Cool video. My dad has this amp still to this day (1992). It sounds great but I’m not surprised there’s evidence of heat inside. A huge design flaw is the cooling fan in the back is not regulated by temperature but volume. If you play music loudly the fan kicks on and keeps the components cool. If you play at low volume the unit just gets hotter and hotter. There were times I’d touch the top and burn my finger if it was playing Christmas Eve music in the background during a family party all day, for example. His A speaker terminal doesn’t work. So he uses the B terminal. Eventually it’ll probably go out as well. Thanks for posting, very informative.
The thermal management strategy Panasonic used in all their 90s-2000s fan cooled gear has got to be one of the worst designs I've seen in a long time. I kept a small fan on my SA-DA10 for this very reason.
Andrew, I replaced both the RSN310R36 H+ modules on a very similar Panasonic unit SA-HT400 (the old ones were blown). It works fine, but it seems to be pulling too much bias current (high idle heat levels of heat sink & power transformer is almost too to touch). How is bias current adjusted.
Thx for the reply .. all seems OK, I just think there was heat buildup/soak due to poor ventilation, since the fan only comes on intermittently at peak bursts .. will setup a separate PC fan to force air thru it full time .. 1) it sometimes doesn’t respond to the main power button on the remote (I checked the remote’s operation) .. IR output is OK .. 2) the Tuner does not work .. white noise on FM .. nothing on AM ... ??? PS, the board/solder joints look great .. no discolored spots from heat .. seems like the amp was rarely used, and has had a comfortable life (it was given to me from a neighbor) ....
hi! first of all, which were the issue symptoms? I own a SU-G90 amp, and after running some time, and more quickier as higher is the volume level, you hear some "electrical" sound, and then the amplifier goes to a "freeze status", turning off the sorrund, the superbass, the dat/vcr input...is that the overload issue? when the amp does taht, i feel it hot. the fan works, and fan's speed is related which amp "charge"...higher volume, higher speed I'm trying to find out what is working wrong... I'm from Bahía Blanca, Argentina, and we don't have good and capable technical services here, so I'm doing some research to solve this...or at least to find the cause... thanks!
That sounds like the problem documented in this video. Also you should remove the old thermal paste and reapply fresh paste between the devices on the heatsink. A thin, evenly applied coating is all that is needed. Silicone base zinc oxide thermal compound is the factory applied paste.
@@MadScientistsLair OK, thanks!!! I will do both things: I will check the board for bad solders, and after that, will renew the thermal paste (the actual one is solid as rock right now, so not doing its work properly) and maybe will add an extra fan to avoid the whole amp getting hot... Thanks for your help. Will keep you informed about how things go on.
as I'm a newbie, I'm facing problems to identify cracked/bad/broken/dried solder joints... my brother had lots of experiencie in electronics, but he passed away last July, due to CoVid...so I'm facing this project by myself...great challenge...
My Amp just started showing the Overload really want to fix them...Please help think I'm having the same problem as Carlos the R704 and R703. Where do I even buy the replacement resister?
Can someone 1 help me please iam in Jamaica i have the su-g91 i am really in need of the 2 icś power pack for this amps can someone 1 help me please were can i get them to buy iam all the way in Jamaica.
hi Andrew - I have the complete system and have had this technics set up and bought it new at Foleys, a long time ago...so today went to listen to music while cleaning and nothing no power I got the click but no lights....I separated everything from it and plugged it in and nothing? what can i do? open it up and check and if the resisters are burned up who works on these things? I have the manual that i found online....man that sucks I have had this for a long time everything else seems to have life expect the amplifier...I appreciate anything you can tell me how to proceed.
It probably has bad solder joints. If you've never done this kind of repair, I would advise against DIY repair. An expert makes soldering look easy because to them, it is. Keep that in mind when you watch videos and get some practice elsewhere before working on gear you actually like. Also do keep in mind that improper service procedures could cause hazardous conditions that include a risk of fire or electric shock.
Hi Andrew hope you can help I have a technics su-x120 amp and having an intermittent fault where it intermittently beeps approximately every 30mins by any chance do you know why this could be doing this
Im not sure what you mean by "cracks". What's cracked? the solder joints or the board? Couldn't really see anything on the video that looked like a crack. Thanks for making the video though. I do feel a little smarter now.
Yep, and someone bought it before I could demo it on camera. It never came back for service under warranty or otherwise so I can only assume that the repair was durable.
@@MadScientistsLair Im no electrician however I'm not afraid of taking a look and it looks the like the exact same problem. The same two circuits look burnt. I'm just not sure if I'm gonna find anyone in my area that is going to be able to repair. Anyway I was seriously stoked to see this video and really appreciate the fact you took time to reply. In my book that makes you a friend. Will continue watching and now a super fan.
@@sergioomar9090 To successfully complete this repair, you need good through hole soldering skills and a good soldering iron that maintains a temperature of about 300-315°C. Too hot and you'll damage the board. Use only rosin flux core leaded solder. Use a multimeter to ensure the large capacitors have discharged; they should do so within 10 minutes of the unit being disconnected. They're a shock and equipment damage hazard if charged when the unit is under service. As always, I must warn that improper servicing techniques and parts selection may cause damage to the unit and can present a risk of fire or serious electric shock. If you're not confident you have the required skills or tools, do not proceed. Obtain the tools and learn proper soldering and safety techniques beforehand.
Hey I have a technics su-g75 (very similar to this one). I've been trying for months to fix the relay/protection circuit. There is no second click after I turn the system on. No sound whatsoever. Any help is appreciated
I changed a variable resistor of the equalizer that went bad for another with a close value and I've had it using it for several years, after doing this one channel worked a little lower, but today I let the audio of one channel come out from the amplifier. It is not cable or speakers and even if I turn off the equalizer, the audio from one channel of the amplifier no longer comes out. Please how can I repair this
hello i have panasonic sa-he7,when i connect input cd,tv,vcr,tape monitor,this falls in volume,about 10db approximately three minutes after user.but put into tuner (fm or am) its volume raises 10db he had lost,if you know which could be the possible failure, or if you have any idea what it could be,i really appreciate it your opinion,greetings
It may be possible to design a standalone support circuit but the circuit would be anything but basic. These modules require four power supplies for just the output stage and a control circuit is required. (Power supplies are VH+, VH-, VL+, VL- ) Datasheets do not exist outside of the very basic info provided in the service manuals for the amps that used this IC.
Oh and just to be perfectly clear: I *do not* recommend any SVI or RSN type hybrid ICs as a basis for any DIY project. They have not been made in 20 years or more. They're too application specific and are harder to make work. There are less expensive alternatives. There are higher performance alternatives
I have the same technics su-g95.My EQ/vcr button does not work when pressed do eq/vcr option and my volume lags when rotated..u have an idea wats wrong.
It's probably suffering from the same problems in the video, just in different circuits. Check solder joints on the front panel boards and at the connectors to the front panel board on the mainboard.
i buy a su g75, someone replaced original fan with a 12V cheap fan conected to a answer machine 220vac-12vdc transformer and put inside the box, i need the original specs of the original t751 sub transformer (ac volts), i try to fix/restore funcionality of the fan drive board , it has been disabled by a prevoius technician.
Update .. I mounted a 200mm PC fan on top, over the vent holes with double adhesive strip, powered by a 5v -1A USB, Apple cell phone (mini white cube) charger, plugged into the switched 120VAC receptacle on the back of the amp .. the fan spins slow at about 240 RPM & draws only 80 ma .. perfect cooling solution ... PS .. would have sent a pic, but can’t on a RUclips comment/reply ...
this amp will show "overload" when volume level triggers fan operation but fan can not turn. often bad contact to fan. use wires. also bad solder at anything screwed to heatsink. input and output jacks also bad solder. you pretty much have to inspect and resolder all over this unit.
This is correct. On average, I spend about 1-2 hours just resoldering and inspecting joints on these and similar time period Technics receivers and amps. They work wonderfully after the repair though so I keep fixing them.
hola amigos soy de Argentina poseo 2 de estos amplificadores TECHNICS SU-G95 en lo personal es excelente su potencial de volumen.Ahora si algunos de ustedes poseen esta misma unidad y al subir el volumen a menos de la mitad y les saltara la proteccion con el mensaje ''OVERLOAD''.Revisar el cooler ventilador si funciona y gira en la parte trasera.Si no llegara a funcionar es el motivo que recaliente x sobrecarga desmontar el cooler y revizar los contactos que no se encuentren sulfatados lijar suavemente sus contactos y probar o buscar un cooler similar!!!
I have the SU G95 and have had it for years! I really like it, plenty of power for me! Just recently it has started flashing overload. I took the shell off to look at it but I don't have a clue about the guts so I just put it back on. I live in Arlington, Texas and don't know anybody I'd know to trust messing with it. I'd like to have it fixed but have recently gone to Best Buy looking at what else I could replace it with. Do you know anybody in the area where I live that are good, or could you look at and repair if I sent it to you Andrew?
+keith bailey It's public, can I send you a message on Hangouts? I'll be in Arlington for a little while as a friend from UTA has invited me to dinner.
yo tengo uno y gual tienen buen sonido lo unico que el cooler o el ventilador no funciona y calienta mucho el qu tenga uno y gual revise vien el ventilador porque la temperatura de calor telo puede quemar por dentro
si el cooler ventilador no funciona te recomiendo no usarlo y urgentemente solucionar el problema podes terminar quemando el integrado ojo yo que vs no lo usaria o le pongo ventilacion aparte
Cool video. My dad has this amp still to this day (1992). It sounds great but I’m not surprised there’s evidence of heat inside. A huge design flaw is the cooling fan in the back is not regulated by temperature but volume. If you play music loudly the fan kicks on and keeps the components cool. If you play at low volume the unit just gets hotter and hotter. There were times I’d touch the top and burn my finger if it was playing Christmas Eve music in the background during a family party all day, for example. His A speaker terminal doesn’t work. So he uses the B terminal. Eventually it’ll probably go out as well. Thanks for posting, very informative.
The thermal management strategy Panasonic used in all their 90s-2000s fan cooled gear has got to be one of the worst designs I've seen in a long time. I kept a small fan on my SA-DA10 for this very reason.
Hey Andrew, I hope all is well! My amp you repaired is still going strong!
Andrew, I replaced both the RSN310R36 H+ modules on a very similar Panasonic unit SA-HT400 (the old ones were blown). It works fine, but it seems to be pulling too much bias current (high idle heat levels of heat sink & power transformer is almost too to touch). How is bias current adjusted.
Bias is automatic. Check solder joints and nearby caps and resistors. Some units run hot but the transformer also running hot has me concerned.
Thx for the reply .. all seems OK, I just think there was heat buildup/soak due to poor ventilation, since the fan only comes on intermittently at peak bursts .. will setup a separate PC fan to force air thru it full time .. 1) it sometimes doesn’t respond to the main power button on the remote (I checked the remote’s operation) .. IR output is OK .. 2) the Tuner does not work .. white noise on FM .. nothing on AM ... ??? PS, the board/solder joints look great .. no discolored spots from heat .. seems like the amp was rarely used, and has had a comfortable life (it was given to me from a neighbor) ....
hi!
first of all, which were the issue symptoms?
I own a SU-G90 amp, and after running some time, and more quickier as higher is the volume level, you hear some "electrical" sound, and then the amplifier goes to a "freeze status", turning off the sorrund, the superbass, the dat/vcr input...is that the overload issue?
when the amp does taht, i feel it hot.
the fan works, and fan's speed is related which amp "charge"...higher volume, higher speed
I'm trying to find out what is working wrong...
I'm from Bahía Blanca, Argentina, and we don't have good and capable technical services here, so I'm doing some research to solve this...or at least to find the cause...
thanks!
That sounds like the problem documented in this video. Also you should remove the old thermal paste and reapply fresh paste between the devices on the heatsink. A thin, evenly applied coating is all that is needed. Silicone base zinc oxide thermal compound is the factory applied paste.
@@MadScientistsLair OK, thanks!!!
I will do both things: I will check the board for bad solders, and after that, will renew the thermal paste (the actual one is solid as rock right now, so not doing its work properly) and maybe will add an extra fan to avoid the whole amp getting hot...
Thanks for your help. Will keep you informed about how things go on.
as I'm a newbie, I'm facing problems to identify cracked/bad/broken/dried solder joints...
my brother had lots of experiencie in electronics, but he passed away last July, due to CoVid...so I'm facing this project by myself...great challenge...
I have a similar one like this can't remember what model when I plugged mine in is made a electrical zapping noise from the power plug
My Amp just started showing the Overload really want to fix them...Please help think I'm having the same problem as Carlos the R704 and R703. Where do I even buy the replacement resister?
Did yours kick on overload and would switch back on, then overload again? Mines doing that, just wondering what you did to fix?
Mine shows overload as soon as it powers up. Not a cooling issue.
Can someone 1 help me please iam in Jamaica i have the su-g91 i am really in need of the 2 icś power pack for this amps can someone 1 help me please were can i get them to buy iam all the way in Jamaica.
Maybe eBay? Good luck getting a genuine one; they're quite difficult to source in the USA as well.
hi Andrew - I have the complete system and have had this technics set up and bought it new at Foleys, a long time ago...so today went to listen to music while cleaning and nothing no power I got the click but no lights....I separated everything from it and plugged it in and nothing? what can i do? open it up and check and if the resisters are burned up who works on these things? I have the manual that i found online....man that sucks I have had this for a long time everything else seems to have life expect the amplifier...I appreciate anything you can tell me how to proceed.
It probably has bad solder joints. If you've never done this kind of repair, I would advise against DIY repair. An expert makes soldering look easy because to them, it is. Keep that in mind when you watch videos and get some practice elsewhere before working on gear you actually like. Also do keep in mind that improper service procedures could cause hazardous conditions that include a risk of fire or electric shock.
Hi Andrew hope you can help I have a technics su-x120 amp and having an intermittent fault where it intermittently beeps approximately every 30mins by any chance do you know why this could be doing this
+FlippinPicker-UK It's probably a fault similar to the one documented here.
Im not sure what you mean by "cracks". What's cracked? the solder joints or the board? Couldn't really see anything on the video that looked like a crack. Thanks for making the video though. I do feel a little smarter now.
Great video but did you repair this one?
Yep, and someone bought it before I could demo it on camera. It never came back for service under warranty or otherwise so I can only assume that the repair was durable.
@@MadScientistsLair Im no electrician however I'm not afraid of taking a look and it looks the like the exact same problem. The same two circuits look burnt. I'm just not sure if I'm gonna find anyone in my area that is going to be able to repair. Anyway I was seriously stoked to see this video and really appreciate the fact you took time to reply. In my book that makes you a friend. Will continue watching and now a super fan.
@@sergioomar9090 To successfully complete this repair, you need good through hole soldering skills and a good soldering iron that maintains a temperature of about 300-315°C. Too hot and you'll damage the board. Use only rosin flux core leaded solder. Use a multimeter to ensure the large capacitors have discharged; they should do so within 10 minutes of the unit being disconnected. They're a shock and equipment damage hazard if charged when the unit is under service.
As always, I must warn that improper servicing techniques and parts selection may cause damage to the unit and can present a risk of fire or serious electric shock.
If you're not confident you have the required skills or tools, do not proceed. Obtain the tools and learn proper soldering and safety techniques beforehand.
Hey I have a technics su-g75 (very similar to this one). I've been trying for months to fix the relay/protection circuit. There is no second click after I turn the system on. No sound whatsoever. Any help is appreciated
I changed a variable resistor of the equalizer that went bad for another with a close value and I've had it using it for several years, after doing this one channel worked a little lower, but today I let the audio of one channel come out from the amplifier. It is not cable or speakers and even if I turn off the equalizer, the audio from one channel of the amplifier no longer comes out. Please how can I repair this
hello i have panasonic sa-he7,when i connect input cd,tv,vcr,tape monitor,this falls in volume,about 10db approximately three minutes after user.but put into tuner (fm or am) its volume raises 10db he had lost,if you know which could be the possible failure, or if you have any idea what it could be,i really appreciate it your opinion,greetings
Hi. Can I use a Stand alone RSN3305 to get any audio out of it using basic circuit ...!?
It may be possible to design a standalone support circuit but the circuit would be anything but basic. These modules require four power supplies for just the output stage and a control circuit is required. (Power supplies are VH+, VH-, VL+, VL- ) Datasheets do not exist outside of the very basic info provided in the service manuals for the amps that used this IC.
Oh and just to be perfectly clear: I *do not* recommend any SVI or RSN type hybrid ICs as a basis for any DIY project.
They have not been made in 20 years or more.
They're too application specific and are harder to make work.
There are less expensive alternatives.
There are higher performance alternatives
Have the same problem by any chance can you tell me the ohm's of the resister R704 and R703. Thank you Good Video
10 ohms, 0.5W, fusible/flameproof type.
Caution! Risk of fire, DO NOT use carbon resistors. Use a fusible or flameproof resistor only.
hi where the full circuit availabe .with full schema.pramo
I have the same technics su-g95.My EQ/vcr button does not work when pressed do eq/vcr option and my volume lags when rotated..u have an idea wats wrong.
It's probably suffering from the same problems in the video, just in different circuits. Check solder joints on the front panel boards and at the connectors to the front panel board on the mainboard.
Mine says overload every time I turn it on, any ways to fix that?
kosama chhay .. “overload” on a Panasonic/Technics Amp/Receiver, usually means the H+ Power Output Module(s) are blown ...
Did you replace and did it fix the problem? Mine is doing the same.
i buy a su g75, someone replaced original fan with a 12V cheap fan conected to a answer machine 220vac-12vdc transformer and put inside the box, i need the original specs of the original t751 sub transformer (ac volts), i try to fix/restore funcionality of the fan drive board , it has been disabled by a prevoius technician.
Update .. I mounted a 200mm PC fan on top, over the vent holes with double adhesive strip, powered by a 5v -1A USB, Apple cell phone (mini white cube) charger, plugged into the switched 120VAC receptacle on the back of the amp .. the fan spins slow at about 240 RPM & draws only 80 ma .. perfect cooling solution ... PS .. would have sent a pic, but can’t on a RUclips comment/reply ...
this amp will show "overload" when volume level triggers fan operation but fan can not turn. often bad contact to fan. use wires. also bad solder at anything screwed to heatsink. input and output jacks also bad solder. you pretty much have to inspect and resolder all over this unit.
This is correct. On average, I spend about 1-2 hours just resoldering and inspecting joints on these and similar time period Technics receivers and amps. They work wonderfully after the repair though so I keep fixing them.
Hola. Alguien sabe donde conseguir el diagrama de amplificador marca Technics.modelo SU-G 95.Gracias.
hola amigos soy de Argentina poseo 2 de estos amplificadores TECHNICS SU-G95 en lo personal es excelente su potencial de volumen.Ahora si algunos de ustedes poseen esta misma unidad y al subir el volumen a menos de la mitad y les saltara la proteccion con el mensaje ''OVERLOAD''.Revisar el cooler ventilador si funciona y gira en la parte trasera.Si no llegara a funcionar es el motivo que recaliente x sobrecarga desmontar el cooler y revizar los contactos que no se encuentren sulfatados lijar suavemente sus contactos y probar o buscar un cooler similar!!!
I have the SU G95 and have had it for years! I really like it, plenty of power for me! Just recently it has started flashing overload. I took the shell off to look at it but I don't have a clue about the guts so I just put it back on.
I live in Arlington, Texas and don't know anybody I'd know to trust messing with it. I'd like to have it fixed but have recently gone to Best Buy looking at what else I could replace it with. Do you know anybody in the area where I live that are good, or could you look at and repair if I sent it to you Andrew?
I live in Carrollton, send it in! Send me a private message and let's schedule a repair.
Not sure if this is private or not. Never have used this before. Let me know what I need to do from here.
+keith bailey It's public, can I send you a message on Hangouts? I'll be in Arlington for a little while as a friend from UTA has invited me to dinner.
I sent you a couple messages, did you get them?
Do you still do repairs? I have this exact problem. Would pay to have it properly fixed!
Hola aver si me pueden ayudar con el diagrama de la tarjeta madre del amplificador technics su_G95 gracias
Hola Nesito el diagrama de este amplificador de casa technics su-G95 porfas
Never liked those big power modules.
alguien save como quitarle el phamtom a este equipo
These are the worst amplifier ever made with those types of power transistors they do not last long I had so many problems with these things
yo tengo uno y gual tienen buen sonido lo unico que el cooler o el ventilador no funciona y calienta mucho el qu tenga uno y gual revise vien el ventilador porque la temperatura de calor telo puede quemar por dentro
si el cooler ventilador no funciona te recomiendo no usarlo y urgentemente solucionar el problema podes terminar quemando el integrado ojo yo que vs no lo usaria o le pongo ventilacion aparte
es plotaron una cosa negra como pilas
Never trust a tech that says “Techniques” 😂 STG that’s not how it’s pronounced
Hi! 🙋♂️What is the power "sub transformer" ?
The smaller transformer is for standby power to enable remote control.
for this reason and a million others i hate technics amps they are highly overrated.