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60in1 Repair Log


Kaizen

Question

I had a couple of 60in1's on the bench tonight, one which had very low audio volume which would decrease over time until you couldn't hear anything and the audio amp heatsink was getting extremely hot and the other board had no sync.

 

No Audio:

At first I suspected the amp was faulty and swapped it out with a known good one which made no difference.

I had another 60in1 which had a sync issues so I had a look at the voltages on both boards and compared the two.

The dodgy board had it's output being dragged down so I started with the audio caps.

I pulled the two 470uF through hole caps at the bottom corner of the board next to the amp and ran them through the cap tester with two significantly different results.

 

Good but not great for a 470uF cap...

 

EPdDjTY.jpg

 

Faulty cap of the same value...

 

VaLmcn7.jpg

 

 

 

I replaced the bad one (circled in red) and audio was restored.

 

w5oeXl0.jpg

 

 

 

No Sync:

You could see there was video on screen and audio was good.

The sync signal was missing when checked on the scope.

I traced it back from the edge connector and it ends up at the output pin 2 on an LV244A buffer at U8 (circled in red).

 

htaGyVc.jpg?1

 

There was a good signal on the input (pin 18) so I swapped it out and video was restored.

 

 

This was my first time repairing these and both were relatively easy fixes, it was my second time swapping out SMD chips and fortunately all went smoothly.

Edited by Kaizen
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Lucky!

 

I had one here with bad sync... the cheap logic chip was OK. The Altera chip next to it was bad. :(

 

I've fixed a few of these with blown resistors in the video output section. Seems folks like to hook these up in cabs with monitors that require iso transformers, yet they can't be bothered to put one in the cab. It blows the sync and video output sections.

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Green = 74LV273 (or HC273) video output latches (commonly blown if isolation transformer is needed but missing)

Orange = Video output ladder resistors (commonly blown if isolation transformer is needed but missing)

Pink = Stereo output DAC for all audio output

 

The square BGA chip just to the left of the audio DAC is the Intel Atom CPU

 

Just below the CPU and its silver crystal is U32, a serial EEPROM for holding configuration data

Just above the CPU is U2, the system RAM

U4 and U6 hold the OS and game code

 

Now, IIRC...

U7 is the voltage regulator for the core voltage.

U36 is the 3.3v voltage regulator

 

60n1.jpg

 

You'll want to read the chips carefully as different boards have different chip families. Some use HC, others LV, others LVT, etc... I think the Chinese just used whatever they had on-hand.

 

These things also suffer from horrible soldering. Check the soldering carefully first.

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Thanks mate, that's a good starting point for these.

They are so cheap that it's not worth fixing them for a fee if you spend meore than an hour on them.

I had a look at these two because I wanted to if they can be repaired and I was lucky that they were both relatively easy repairs with negligible parts costs.

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