Question about Lasonic TRC-931 Cassette Boombox

2 Answers

Pioneer SA 9800 Ampliffier Output transistor going off frequently

I have problem with my Pioneer SA 9800 as 2SC 2525 & 2SA 1075 going off frequently. Has changed it twice. unable to trace fault. I am told that there is a proble with protection circuit.

Posted by on

2 Answers

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Superstar:

    An expert that got 20 achievements.

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

  • Master
  • 1,056 Answers

I assume these are the complimentary pair that drive the speakers. On one of the speaker. You know I think you have a short in the speaker that it drives. Speaker can fuction even if there was a problem with it. I think what happened is when the original transistors shorted out it overloaded the speaker, but not to a point where it is burnt. There is nothing that can overload a power transistor except the speakers, I design a lot of amplifiers, the base input can overload it if you put dc in there, but that would make a the sound all distorted, I assume the sound seem fine. Solution is try connecting a known good speaker and I bet it wont burn out anymore. Even if the speaker look fine don't trust it.

Posted on Jun 30, 2009

×

  • Level 1:

    An expert who has achieved level 1.

  • Contributor
  • 3 Answers

Change your differential transistors in the front end of the power amplifer board,most likely your speaker output 0v is flucturating causing the protection circuit to kick in thus switching off your speakers intermittently.
get a qualified tech help.

Posted on Aug 24, 2009

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

The type of audio power and the number on onkyo A917 amplifier


Hi
Usually there are 2 transistors for each channel, if you don't know the numbers on the transistors.
there is another way to get as close as possible to have equal or similar to the same type of transistors (NPN/PNP)
example: 2SA is PNP transistor.
there are (2SA/2SC) transistors and there are (2SB/2SD)
complementary transistors
1: you have to know the supply voltage for the transistors
2: choose transistors that it is equal to the current and voltage that suits the supply voltage.
follow this link to find suitable transistors.
be aware and be careful that there other parts you need to check on the power amplifier circuit, resistors,capacitors and drivers etc...
I would suggest (2SD1047/2SB817)

http://www.smcelectronics.com/DOWNLOADS/COMPTRANS.PDF
Good luck
Hope this helps

Jun 25, 2016 | Onkyo Audio Players & Recorders

1 Answer

Need service manual for pioneer sa-600


Head straight to the (European) electrotanya website, which offers free downloads of a wide range of service manuals. No registration is required either.

The Pioneer SA-600 schematic shows both voltages and currents. For this amp, the total current for left & right output modules (no signal) is 60mA. No-load voltage is 58 volts, dropping to 48 volts (one channel driven, 25 watts out).

PIONEER SA 600 SCH Service Manual free download schematics eeprom...

Feb 26, 2014 | Cameras

1 Answer

Pioneer model SA 9500 stereo amplifier problems.


Is the dc voltage reading on the base of the outputs 0.6 with emitters reading 0.014 or there about. Depending on the outputs used you might read 1.2volts on the base. Your collectors will read the power supply voltage of 50 or 60volts or more. If this is what you are reading on your meter the problem is in the speaker protection circuit. This circuit is what drives the relay you tested.

Jun 27, 2012 | Pioneer Audio Players & Recorders

1 Answer

Key to tx-green lite out-no output power or red lite rec ok


It could be small transistors--in the back where the light and transmit hook up. One small transistor will shut down transmit & possibly receive. Get it serviced at a radio repair shop. if you know how do it yourself. Change all small transistors to 2sc3904 or 2sc 3906 at "Radio Shack."

Apr 30, 2011 | Cobra 29 LTD CB Radio

1 Answer

Output stage scheme for pioneer vsx-d1 channel floating negative.


It should be a push pull. The fact that you have negative voltage almost certainly means push pull. One side will be constructed using NPN transistors ran off the positive DC rail and the other side will be constructed using PNP transistors ran off the negative rail. I don't know the age of your amp but I know pioneer now uses integrated amp modules instead of discrete transistors.

http://pdf1.alldatasheet.com/datasheet-pdf/view/82968/SANYO/STK412-020.html

example of integrated amp module (sorry for the chinese)

Feb 11, 2010 | Audio Players & Recorders

1 Answer

I have a teac a717 amp which is blowing both 5A fuses.


Thanks for the clarification. From the fuse behavior and feeding the amp into another amp (generally a no-no) it almost certainly is in the output section. If the amp used output transistors (numbered something like Axxxx/Cxxxx where xxxx=0000-9999) there will be some white three-legged low value (.47 ohm or less) resistors that are probably open. FYI the full part numbers for the transistors would be 2SA/2SC so a part marked C3281 would need a 2SC3281. B+D Enterprises (Google them) has most Japanese semiconductors and they have never sold me a fake transistor.

For more repair tips check out www.audiokarma.org

Dec 27, 2008 | Audio Players & Recorders

1 Answer

Power On + red LED turns on + but final relay (click) don't come so no sound


Your audio output transistors are shorted and your unit is staying in "protect " mode to protect your speakers from 40 to 60 volts that is being sent at them from the shorted outputs. If you can use a meter you won't need the schematic MOST likely because the outputs are USUALLY the only parts that short out. The output transistors( or chip ) are mounted to the large, finned heatsink. The #'s on the transistors start with "2SA-" and "2SC-" followed by numbers. There are two output transistors per channel. If your unit uses an IC for audio output then the # on the IC will be "STK-" followed by numbers. These parts are available from tritronicsinc.com. Good Luck!

barneyluc

Oct 17, 2008 | Denon PMA-2000R 2-Channel Amplifier

1 Answer

Pioneer amph sa 9500 II


Hi yalazogeday

Your amp is fitted with two 2SD588A (NPN) and two 2SB618A (PNP) power transistors in the output stages. Click on the part for a place to get them from. These parts are no longer available from Pioneer, nor are the prescribed replacements. (the amp was built in 1978) Because of the unusual transistor package used, you may have to upgrade to a more modern transistor, and modify the mounting also.

robotek


May 24, 2008 | Audio Players & Recorders

1 Answer

Parts replacements


This is straight from the 1989 Japanese Transistor Substitution Manual.......

2SA 1011--------use 2SB 1085 A, made by Rohm

2SC2344---------use 2SD 1562A, made by Rohm

Good luck...Rob

Jan 31, 2008 | Audio Players & Recorders

Not finding what you are looking for?
Lasonic TRC-931 Cassette Boombox Logo

Related Topics:

1,047 people viewed this question

Ask a Question

Usually answered in minutes!

Top Lasonic Audio Players & Recorders Experts

Jonathon summesfield

Level 2 Expert

285 Answers

Joseph Hoffmann

Level 3 Expert

1702 Answers

ka4iup
ka4iup

Level 3 Expert

3957 Answers

Are you a Lasonic Audio Player and Recorder Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...