ks-ax302 JVC

rrae · 01:06 PM

Got this amp for repair. sound from outputs - high frequencies sounds disorted, when all filters are off. When comes bigger bass - amp is shutting down, green light turns off. What should look for? Power and output transistors seems to be okey. But seems like this amp was repaired before. KTD998 has replaced with this, i guess, 2sd998. Why there is such a difference with size? Is it ok to leave it and dont replace? I have service manual.

Perry Babin · 19th August 2011, 06:04 PM

Not all 2Sx... convert to KTx... These are entirely different transistors (inside and out).

Are you saying that the large transistor was replaced by the smaller transistor in a previous repair? If so, that won't work. Not even the pin configuration is the same.

rrae · 19th August 2011, 06:09 PM

Only one transistor was replaced with this 2sd.

Perry Babin · 19th August 2011, 06:15 PM

Email me the service manual.
babin_perry@yahoo.com

Which transistor was replaced with the smaller one?

rrae · 19th August 2011, 06:45 PM

Perry, I was looking at datasheet and I didnt found difference
KTD998 KTD998 pdf, KTD998 description, KTD998 datasheets, KTD998 view ::: ALLDATASHEET :::
2SD998 http://www.svntc.com/TPDF/1698.pdf
manual sent, i will take a look which one was replaced.only one KTD998 was replaced with 2SD99. I should check the other channel output sound.

Perry Babin · 19th August 2011, 09:41 PM

The datasheets you have are both for the larger transistor. The smaller transistor is obsolete so it's difficult to find the datasheet for it. You will have to get the larger KTD998 or an equivalent transistor.

From the service manual, it appears that the transistors are clamped down by a plate. If that's the case, you should be able to use the FJA4313 and FJA4213 as subs (to replace both outputs in the defective channel).

Also check the emitter resistors to confirm that they're within tolerance.

rrae · 20th August 2011, 07:29 PM

Well, You suggest to replace KTB778 with FJA4213 and KTD998 with FJA4313? If so, then i will order. I looked at datasheets and I was thinking, that they will not work as substitutes.

Perry Babin · 20th August 2011, 07:32 PM

What makes you think they're not good subs?

If yours have an insulated back on them, you will need to add insulators between the transistor and the heatsink for the FJA parts.

19th August 2011, 01:02 PM	#1
rrae diyAudio Member Join Date: Mar 2011	ks-ax302 JVC Got this amp for repair. sound from outputs - high frequencies sounds disorted, when all filters are off. When comes bigger bass - amp is shutting down, green light turns off. What should look for? Power and output transistors seems to be okey. But seems like this amp was repaired before. KTD998 has replaced with this, i guess, 2sd998. Why there is such a difference with size? Is it ok to leave it and dont replace? I have service manual. __________________ DMM Last edited by rrae; 19th August 2011 at 01:06 PM.

19th August 2011, 06:04 PM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Not all 2Sx... convert to KTx... These are entirely different transistors (inside and out). Are you saying that the large transistor was replaced by the smaller transistor in a previous repair? If so, that won't work. Not even the pin configuration is the same. __________________ Links >> Basic Car Audio Amp Repair * Basic Car Audio Electronics * New Site * Basic Switching Power Supply Design * Basic Computer Skills << Links

19th August 2011, 06:09 PM	#3
rrae diyAudio Member Join Date: Mar 2011	Only one transistor was replaced with this 2sd. __________________ DMM

19th August 2011, 06:15 PM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Email me the service manual. babin_perry@yahoo.com Which transistor was replaced with the smaller one? __________________ Links >> Basic Car Audio Amp Repair * Basic Car Audio Electronics * New Site * Basic Switching Power Supply Design * Basic Computer Skills << Links

19th August 2011, 06:45 PM	#5
rrae diyAudio Member Join Date: Mar 2011	Perry, I was looking at datasheet and I didnt found difference KTD998 KTD998 pdf, KTD998 description, KTD998 datasheets, KTD998 view ::: ALLDATASHEET ::: 2SD998 http://www.svntc.com/TPDF/1698.pdf manual sent, i will take a look which one was replaced.only one KTD998 was replaced with 2SD99. I should check the other channel output sound. __________________ DMM


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19th August 2011, 09:41 PM	#6
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	The datasheets you have are both for the larger transistor. The smaller transistor is obsolete so it's difficult to find the datasheet for it. You will have to get the larger KTD998 or an equivalent transistor. From the service manual, it appears that the transistors are clamped down by a plate. If that's the case, you should be able to use the FJA4313 and FJA4213 as subs (to replace both outputs in the defective channel). Also check the emitter resistors to confirm that they're within tolerance. __________________ Links >> Basic Car Audio Amp Repair * Basic Car Audio Electronics * New Site * Basic Switching Power Supply Design * Basic Computer Skills << Links

20th August 2011, 07:29 PM	#7
rrae diyAudio Member Join Date: Mar 2011	Well, You suggest to replace KTB778 with FJA4213 and KTD998 with FJA4313? If so, then i will order. I looked at datasheets and I was thinking, that they will not work as substitutes. __________________ DMM

20th August 2011, 07:32 PM	#8
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	What makes you think they're not good subs? If yours have an insulated back on them, you will need to add insulators between the transistor and the heatsink for the FJA parts. __________________ Links >> Basic Car Audio Amp Repair * Basic Car Audio Electronics * New Site * Basic Switching Power Supply Design * Basic Computer Skills << Links

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