EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: CrazyTiger on August 22, 2022, 05:53:45 am
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Hi,
I am trying to repair a 8562EC Spectrum which is not turning on. The power supply is doing a on and off cycle. I have looked into all most of the major startup area and secondary area, so far I am yet to find anything shorted or open.
To be sure I have also removed and checked all the FET out of circuit, capacitors tested and mosfet driver IC's been replaced as well. Everything looks good so far, except few capacitors which I have replaced.
Looking at the small board, I have my doubt on a component marked LT2105, I am able to find this being sold in aliexpress, but I am not able to find a datasheet for this chip. I can find a LT210 but not 2105 Any idea what this chip could be?
(https://i.imgur.com/MJcGiIO.jpg)
(https://i.imgur.com/t8dzAlY.jpg)
(https://i.imgur.com/fOpiEpu.jpg)
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It is a 5V ultra low drift 5ppm/oc voltage reference LT1021.
https://www.analog.com/media/en/technical-documentation/data-sheets/1021fc.pdf (https://www.analog.com/media/en/technical-documentation/data-sheets/1021fc.pdf)
Also, have you downloaded the maintenance manual for 8562EC at the following site, which has a very detailed troubleshooting procedures regarding the 1.5 second "on/off kicking" startup of the power supply on Page 624?
https://www.testunlimited.com/pdf/an/08562-90219.pdf (https://www.testunlimited.com/pdf/an/08562-90219.pdf)