collapse

Author Topic: Unicord Stage 65b Output Transistors  (Read 211 times)

Sfmag1

  • Chipper
  • *
  • Posts: 4
  • Chip Points: 0
    • View Profile
Unicord Stage 65b Output Transistors
« on: April 29, 2019, 02:00:22 AM »
Hello. I have been working on a Unicord "Stage" 65b amplifier and ordered and installed replacement output transistors Sanyo B507E and D313E. They work alright with a signal from a generator or guitar at very low volume but  heat up and will burn/short out completely if left on with a louder volume setting. The sound is good out of an 8 ohm speaker until it is turned up, then they heat up. They would be normally mounted to the chassis to dissipate heat but they are burning hot anyway. The speaker reads ok at 8 ohms. I am suspecting the Chinese transistors I bought from e-bay are cheap junk and that is the problem. Any experience or advice on this? Should I buy an equivalent?
Tx

phatt

  • Legendary
  • ******
  • Posts: 1992
  • Chip Points: 236
    • View Profile
Re: Unicord Stage 65b Output Transistors
« Reply #1 on: April 29, 2019, 03:44:36 AM »
Hello. I have been working on a Unicord "Stage" 65b amplifier and ordered and installed replacement output transistors Sanyo B507E and D313E. They work alright with a signal from a generator or guitar at very low volume but  heat up and will burn/short out completely if left on with a louder volume setting. The sound is good out of an 8 ohm speaker until it is turned up, then they heat up. They would be normally mounted to the chassis to dissipate heat but they are burning hot anyway. The speaker reads ok at 8 ohms. I am suspecting the Chinese transistors I bought from e-bay are cheap junk and that is the problem. Any experience or advice on this? Should I buy an equivalent?
Tx

ARRRRH,,  :o  Stop!!!  :o They have to be mounted BEFORE you turn on anything.
That is why the heat sink is there,, they cannot work without a heat sink.
Phil.

Enzo

  • Legendary
  • ******
  • Posts: 1835
  • Chip Points: 187
    • View Profile
Re: Unicord Stage 65b Output Transistors
« Reply #2 on: April 29, 2019, 07:45:03 PM »
Agree^^^

ALWAYS put the power transistors on the heatsink before powering up.


How long would you run your car engine with zero water in it?  Or with zero oil in it?

Sfmag1

  • Chipper
  • *
  • Posts: 4
  • Chip Points: 0
    • View Profile
Re: Unicord Stage 65b Output Transistors
« Reply #3 on: April 30, 2019, 06:49:58 PM »
Ok noted and will try. ??? 
« Last Edit: April 30, 2019, 07:01:32 PM by Sfmag1 »

 

* User Controls

 
 
Welcome, Guest. Please login or register.
Did you miss your activation email?

* Recent Posts

Another Randall RG100ES question by vidmachine
[May 22, 2019, 11:17:47 PM]


Peavey Stereo Chorus 212 by vidmachine
[May 21, 2019, 12:58:44 PM]


Crate gx900h by Basill
[May 21, 2019, 09:19:36 AM]


Heathkit TA16 by GlenF
[May 12, 2019, 10:33:44 PM]


Dual or Split supply Audio amps by phatt
[May 07, 2019, 05:11:13 AM]

* Sponsors