8 replies to this topic

[Oliver]

Hi there,

Just got a VCS sold as spares or repair. It looked as though it had been kept in a damp environment as the switches and alloy shielding was covered in white corrosion.

I stripped and cleaned it carefully and it does work although the best i can get is a very poor image on screen. I have tried adjusting the RF modulator and have resoldered a number of dry looking joints.

Any ideas? Knackered RF modulator?

Any advice much appreciated.

KR,

Oliver

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[akaviolence]

I read this once and copied the info to a txt file, no idea if it will help, but easy to try:
"You may also want to replace the "green chicklet" capacitor on the board. (C241) That always does the trick for me!

Poly Film .1uF (100V) "

[Oliver]

Thanks for that. I will replace that capacitor, and a few others.

KR,

Oliver

[akaviolence]

Please let everyone know if it helped at all. In fact if you can, do one at a time and test the results each time to narrow down what cap helped most.

[zylon]

Sometimes, just cleaning the ends of the RF cable works wonders. Also might need to replace it. Either way, I'd say it's definitely cheap and simple.

[Oliver]

Hi everyone,

Thank you all for the advice so far.

Unfortunately I momentarily forgot the saying 'if it isnt broke don't fix it'. Whilst waiting for my new capacitors of various types to be delivered I replaced the voltage regulator. I just could not restrain my soldering iron.

I wish I had left it alone. Now I am only getting a blank (black) screen when I power up the console. Any ideas what I have blown up? I have refitted the original VR to no avail.

I am determined to fix this, and have the field service manual. Unfortunately although I rate my soldering skills pretty highly I am obviously crap at fault finding!!!

Please help, tell me what to replace!

Summary of symptoms: Black screen on power up.

KR,

Oliver

PS this is the VR I used:


7805 5 volt Voltage Regulator I.C.
Voltage Regulator Type:3-Terminal Fixed Positive

• Max Input Voltage:25V
• Max Output Voltage:5V
• Max Output Current:1.5A
• Dropout voltage:2V
• No. of Outputs:1
• Min Supply Voltage:7V
• Max Supply Voltage:25V
• Termination Type:Through Hole
• Case Style:TO-220
• No. of Pins:3
• Operating Temperature Range:0°C to +125°C
• Max Operating Temperature:125°C
• Min Temperature Operating:0°C
• Base Number:7805
• IC Generic Number:7805
• Logic Function Number:7805
• Min Input Voltage:7V
• Output Voltage:5V
• Voltage Regulator IC Case Style:TO-220
• Voltage:5V

Edited by Oliver, Wed May 11, 2011 9:22 AM.

[zylon]

I'm wondering if you didn't accidentally bridge a terminal and fry a chip.
Black screen is usually (not always but...)the sign of fried IC. Or could be just loose. Try reseating the chips and check for breaks in the traces by v-regulator.

[Oliver]

zylon, on Wed May 11, 2011 4:59 PM, said:

I'm wondering if you didn't accidentally bridge a terminal and fry a chip.
Black screen is usually (not always but...)the sign of fried IC. Or could be just loose. Try reseating the chips and check for breaks in the traces by v-regulator.

Thanks for that. I have an Atari 1050 drive which I think has a 6507 if so I could try changing that.

[zylon]

Oliver, on Thu May 12, 2011 5:57 AM, said:

zylon, on Wed May 11, 2011 4:59 PM, said:

I'm wondering if you didn't accidentally bridge a terminal and fry a chip.
Black screen is usually (not always but...)the sign of fried IC. Or could be just loose. Try reseating the chips and check for breaks in the traces by v-regulator.

Thanks for that. I have an Atari 1050 drive which I think has a 6507 if so I could try changing that.

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