Amiga 600 game port up and left not working

[F0LLETT]

One question, do you have a 1MB RAM expansion?
If so remove it and see if issue is resolved. Seen loads of this type of issue with dodgy trapdoor connection issues with RAM card.

[F0LLETT]

Guess he means M1V. Have to be fair, worked on hundreds of A600's. Never once had an issue there.
Sometimes the 4.7 Ohm 5V feed resistor, but thats generally when someone shorts out 5V rail when inserting metal mouse or joystick connectors.

Just to give an update on this issue;

So I ordered the U34 chip from ebay (from a seller in Italy) - I managed to remove the chip with a soldering iron without ripping the pads (I don't have access to Hot Air Station) by flooding the chips pins with solder, wicking up the solder and slowly lifting each pin. I replaced the chip but the behaviour still persisted with up and left not working on the joystick.

So in my frustration I attempted to repeat the process as I received 5 chips from Italy but this time I ripped about half the pads the chip sat on - I attempted to retrace these and a put a new U34 back on - at this point it was a total mess and now the mouse only half worked and only fire worked.

So I had to send off my Amiga 600 to Luke at Retro Six for repair (Cost me £60) - who I can't recommend enough (Guys is a Wizard with this stuff!)

He posted a tik tok video of the repair on the retro six tick tok page (also his facebook page) of him repairing my mess.

He also mentioned to me that the resistor on the MV1 line (68R termination resistors) had burned out which he said is starting to be very common.

Hope this helps someone!

Thanks for the help from the previous people who replied.

[F0LLETT]

I've also worked on hundreds of A600 and haven't seen that either.  Not even sure how the resistor could 'burn out' in that position, it connects a low current TTL output to a high impedance input.  The original post suggested that the problem might have been intermittent, in which case it was more likely that the resistor was cracked as opposed to 'burnt out'; possibly lost in translation.  Obviously it can't un-burn out, then re-burn out again. Have seen plenty of cracked resistors and inductors before which can cause permanent or intermittent faults.

A bit more simple fault tracing would have confirmed if U34 was defective or not and would have avoided both the mess and expense.

Ah yes, cracked resistors. Bloody annoying. Going round in circles, checking components you know are going to be faulty. Only to find they read correctly, due to you pushing on them with meter probs, .