Greetings to all, I have a Scott 350r which has loss of output on the left channel. This is same for AorB speaker hook up. I am a novice, but with some dircetion think I can solve the problem. This is background I know: 1) found a resitor had become hot, and darkened board. I cleaned board,made repair. no overheating, but no still no sound on left channel either. The way the amp powers up seems odd to me. As I percieve it, power is from swithch to 2 Electyc Caps. but is then "interupted unitl the correct power is reached or"balanced " as to give a specific voltage to the unit. This is where I am lost as there are feeds from power switch directly to speaker outputs. There sems to be power at this power "block" . I removed power switch, cleaned, have plugged,swapped, back and forth to verify any connection cables etc. What i am asking is if anyone can guide me through the path from power switch to speaker output in a step by step to deteermine where the hitch is. PLEASE HELP. Much thanks in advance, Please respond as soon as tukey tranquilzer wears off, Paul in Portland,Oregon
Hi,
Did you check the F3 4 amp fuse? The speaker output wire it is soldered to the edge board eyelet 51 to the fuse then to the switch and last to the speaker output J9 connector. It is possible the fuse it is blown.
Did you check the F3 4 amp fuse? The speaker output wire it is soldered to the edge board eyelet 51 to the fuse then to the switch and last to the speaker output J9 connector. It is possible the fuse it is blown.
Hello Heespaul, fault finding on audio equiemt takes time to learn whats going on within the amplifier circuit.. Some advice on here many confuse you.
The first thing to is carry out some channel resistor checks followed by transistors etc.
If you've got a working channel use this to note voltage checks to solve the faulty channel.
The first thing to is carry out some channel resistor checks followed by transistors etc.
If you've got a working channel use this to note voltage checks to solve the faulty channel.
Thanks for your attention to my posting as issue lies within this section. Have not done point to point on this circuit. Will do so. Fuses appear OK but did not change exisitng fuses. Fuse may be defective. Will follow direction and keep you posted. Thanks much for your help,Cheers,Paul
Amptech, Thanks much for your help with this. I get intimidated by the complexity of the solid state electronics and common sense approach goes away. I am grateful for your insight and helping me to understand how diagnosis requires a logical process. Resistor # R233 was getting hot. I replaced this resistor but no change.The oppisate or same resitor on right channel is R236. I will check the path on working channel and then do same to other. It is so simple I am embarrased. I truly appreciate your time and help on this. I learn by trying it myself but realy learn when others like yourself share expertise. I love this equipment and hope to revive it. Thanks much, will keep you posted. Cheers,Paul
....classic
amplifier doesn't work in ch B unless you crank some amount of volume
fault finding :
set up the amp at the point when ch A is operative while ch B is not tackle over the protection relay with a pencil or anything plastic and voila !!!!
Repair :
replacing the relay will solve the problem though in an amplifier of such an age other things will need to be repaired also electrolytics inside are probably dead , trimmers are probably very dirty , pots and switches likewise and expect some soldering issues also .
sakis
www.fast food solutions .com😀😀😀
amplifier doesn't work in ch B unless you crank some amount of volume
fault finding :
set up the amp at the point when ch A is operative while ch B is not tackle over the protection relay with a pencil or anything plastic and voila !!!!
Repair :
replacing the relay will solve the problem though in an amplifier of such an age other things will need to be repaired also electrolytics inside are probably dead , trimmers are probably very dirty , pots and switches likewise and expect some soldering issues also .
sakis
www.fast food solutions .com😀😀😀
Heespaul, if possible can you post the model number of the amplifier so we could check for schematic.. What is the value of 236 and what is it tied to such as a input transistor or driver stage? Resistors heating up would indicate a shorted component or open circuit within the circuit
If possible load picture of your amp do we can advise more on this fault.
If possible load picture of your amp do we can advise more on this fault.
scott 350R left channle signal loss
Amptech, The model is 350R/350RL (350rl european version). Forgive me but I havn't got to testing circuits yet. DMM needed new batteries. Will perfrom test tonight and get results to you.
The r233 burnt board slightly. I ran point to point when I replaced this resistor. After repair I noticed an increase in left output power meter but not a real increase in volume. I attached a link to a free servcie manual website. You may want register as they are a good resource for free stuff. Here it is the link: HiFi Engine | Download Free User/ Service Manuals, Amplifier, Receiver, CD, Tape, Tuner, Video You can use my login info: name: heespaul, password is hees1317. Just log in a downlaod a service manual for a HH Scott 360r. I am truly grateful for your help. No one has ever on any of the audio forums sites has ever helped me like you have. It is hard for me ask for help so it is a big deal. I can fix the amp. I am a novice but can solder and use a DMM. I trying to learn this stuff and am trying to save all the classic audio stuff I can get my hands on. I have two of these amps. I also have a Scott 460 with the other 350R is for my main amplifier. I am working on a bunch of tube stuff know and sell tubes. I can't tell you enough how much I appreciate you taking interest in my repair on this amp I will test and get to you tonight for tomorrow review. I will forward close up photos in another message.
Cheers, Paul
Amptech, The model is 350R/350RL (350rl european version). Forgive me but I havn't got to testing circuits yet. DMM needed new batteries. Will perfrom test tonight and get results to you.
The r233 burnt board slightly. I ran point to point when I replaced this resistor. After repair I noticed an increase in left output power meter but not a real increase in volume. I attached a link to a free servcie manual website. You may want register as they are a good resource for free stuff. Here it is the link: HiFi Engine | Download Free User/ Service Manuals, Amplifier, Receiver, CD, Tape, Tuner, Video You can use my login info: name: heespaul, password is hees1317. Just log in a downlaod a service manual for a HH Scott 360r. I am truly grateful for your help. No one has ever on any of the audio forums sites has ever helped me like you have. It is hard for me ask for help so it is a big deal. I can fix the amp. I am a novice but can solder and use a DMM. I trying to learn this stuff and am trying to save all the classic audio stuff I can get my hands on. I have two of these amps. I also have a Scott 460 with the other 350R is for my main amplifier. I am working on a bunch of tube stuff know and sell tubes. I can't tell you enough how much I appreciate you taking interest in my repair on this amp I will test and get to you tonight for tomorrow review. I will forward close up photos in another message.
Cheers, Paul
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