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Electronics => Repair => Topic started by: AlexB on September 18, 2017, 02:06:35 pm

Title: KODEN Echo Sounder CVS-126 - defective SDRAM
Post by: AlexB on September 18, 2017, 02:06:35 pm
Hello


I found defective SDRAM  in  KODEN Echo Sounder CVS-126.  It gets very hot, very fast.  (the one on the right).

The LCD won't show anything, just the backlight turns on  and  ON/OFF  is working.

An external fuse blew and when it was replaced, the echo sounder wasn't working anymore.  I think it was a voltage spike.


Part number on SDRAM chip:                          MT48LC8M16A2P-75 IT:G

Closest part number I found in stock for sale:  MT48LC8M16A2P-75 IT:GTR

http://static6.arrow.com/aropdfconversion/25b8a7613c57009f764d08e18edc9430887d9f32/473128mb_x4x8x16_sdram1.pdf (http://static6.arrow.com/aropdfconversion/25b8a7613c57009f764d08e18edc9430887d9f32/473128mb_x4x8x16_sdram1.pdf)


I don't understand what TR ending means.

Maybe GTR is a new code for revision ?   I couldn't find in any datasheet the code GTR or TR.


Thank you


PS:  Maybe someone could help me find the service manual (just in case I would need it).   Thank you


(https://s26.postimg.org/vf3tycj3p/IMG_5565.jpg) (https://postimg.org/image/vf3tycj3p/)

(https://s26.postimg.org/yzzphknn9/IMG_5566.jpg) (https://postimg.org/image/yzzphknn9/)

(https://s26.postimg.org/dsvytkb05/IMG_5570.jpg) (https://postimg.org/image/dsvytkb05/)

(https://s26.postimg.org/6bmreclh1/IMG_5567.jpg) (https://postimg.org/image/6bmreclh1/)

(https://s26.postimg.org/sq918bdmd/IMG_5568.jpg) (https://postimg.org/image/sq918bdmd/)

(https://s26.postimg.org/yfp9smjsl/IMG_5569.jpg) (https://postimg.org/image/yfp9smjsl/)
Title: Re: KODEN Echo Sounder CVS-126 - defective SDRAM
Post by: Armadillo on September 18, 2017, 02:35:58 pm
A fish finder. Ahh, I repaired one color Lowrance before which is tight sealed dead.
I am surprised your koden can be opened so easily.
Seems like the manufacturer of these things are very tight lipped, can't find the manual for the Lowrance either.
But the circuit should be all the same except the algorithm, method of pulsing, I think.




Title: Re: KODEN Echo Sounder CVS-126 - defective SDRAM
Post by: wraper on September 18, 2017, 02:40:53 pm
TR means tape and reel packaging. Part is the same. All you should care is MT48LC8M16A2P-75 in the part number and correct package. Actually you don't even need -75, any other speed grade will do as this is the worst speed grade available.
Title: Re: KODEN Echo Sounder CVS-126 - defective SDRAM
Post by: AlexB on September 18, 2017, 02:45:36 pm
Thank you very much

Yes, it was VERY easy to open.    Just a plastic cover which came out using a screwdriver (covering the edges of the LCD and the screws), and 7 screws.
Title: Re: KODEN Echo Sounder CVS-126 - defective SDRAM
Post by: wraper on September 18, 2017, 02:53:06 pm
BTW check if supply voltage for RAM IC is correct. I's not common for SDRAM to fail frying hot by itself.
Title: Re: KODEN Echo Sounder CVS-126 - defective SDRAM
Post by: AlexB on September 18, 2017, 04:09:15 pm
Yes, I will.  Thank you
Title: Re: KODEN Echo Sounder CVS-126 - defective SDRAM
Post by: ervin on January 17, 2020, 11:53:29 am
Hi can you read bin file of S29JL064H70TFI000 , i have one corrupted need to reflash it  :scared: