Leaderboard

A quick update, i thought i had got rid of this strange reset issue but alas i had not (well i have now). So running on the golden nudge it cart, 9 times out of ten when you got nudges it would work, however with its own nippy nudger cart it rarely would, normal gameplay fine but as soon as you nudged it would reset. Wiring between the two carts slightly different as it uses different lamp outputs for nudge feature and the coin lockout and one of the meters are swapped. Anyway by total accident i realised it was only when the four lamps in the nudge panel were flashing and you nudged it would reset, take the lamps out and it would be fine, now psu is ok all recapped and new regulator, 5.1v very steady but a 0.4v drop on the 15v (15.2v) when lamps flashing. I was only getting 8.6v across the 9.1v zener but that could well be within tolerance. At this point i cheated a little as the only 9.1v zener i have is a stud mount diode so i put an 8.2v zener in (i do recall Barcrest released some notes on MPU3 about changing the zener on low voltage sites, not that mine is low). It works fine now every time. So maybe it is an iffy zener transistor or resistor on the voltage sense circuit (i dont care now it works)

More to come, if you don't mind... My display was completely malfunctioning. But after cleaning and lubricating all the connectors, it's back to normal. (I used brake cleaner and a very small amount of silicone lubricant.) It's probably also because I properly insulated the PCB's mounting points. This prevents short circuits. As you can see in the photos, I used two layers of heat-shrink tubing. I had already done this on the first MPU, but on this one, I had to double it up. Overall, it works; the hold function and sound are still an issue. Plus a few other minor things here and there. Thanks Have a good weekend. Sorry, I can't seem to reduce the video size. Afficheur qui délire.mp4

Whoooo - oooo - ooo 👻 Better (absurdly) late than never! Incoming shortly. (Probably not worth the wait lol)

For the sound it's worth checking that you're seeing the 15v on the collector of T11, if you haven't already. IC3 only delivers the basic sound bleeps, the main sounds come from IC2. Not sure which one supplies the error sounds? For the Hold button it's possibly one of the associated diodes in the switch matrix unless it's affecting other switches you may not have noticed yet. In that case it could be IC22 or one of the caps C24-28 going short. It's quite easy to fault.

Still not here yet! hoping in the next few weeks

Hello experts So, Bob is right. I installed the wrong component: T56. 🙄 I was really incompetent. This board has already been repaired, and the previous owner installed the wrong component, BC172. I always check the component and the schematic; and on the schematic, it's a BC172. Hence the mistake. Now it starts; yes; Bingo! 🙂 😀 Thank you; thank you again. But, well, there are some problems: The sound; I'm going to replace T11. The display is acting up a bit. One scroll bar is stuck in HOLD mode. And others... I'm going to check the connectors, the soldering, etc. Thank you very much.

Hello. My studs are made of metal; what a shame. They'll stay that way; they're well insulated now. Yes, the push-button switch isn't stuck; that's the first thing I checked. I'll double-check this whole area before replacing IC4. As Bob said, it's not easy to do inside the cabinet. jjmXXX; it's a normally closed (NC) contact; if I disconnect a wire, it's the opposite. Thank you for following this adventure.

Does it still do it if you disconnect a wire from the back of the switch?

Those studs are made of plastic (or they should be) so they won't need insulating? The only metal ones are the two fixing the board to the chassis and two holding the ROM cart holder. Before replacing IC4 I would check if any other switches on the same line are working. I would also find out exactly which one it's on (9 or 10) then see what switch it is on the black connector and also the DIL switches. If you can find what they do it will be easy to check that IC4 is OK. You could put the scope on it and see if there's a waveform going in to IC22. With no switches operated there shouldn't be. Are you sure the switch isn't stuck on?

https://www.fruit-emu.com/forums/files/file/843-topgear-1280-dx/?fbclid=IwY2xjawPqHSVleHRuA2FlbQIxMABicmlkETBpRnNnRENYRFNEeE5GcXZsc3J0YwZhcHBfaWQQMjIyMDM5MTc4ODIwMDg5MgABHpXGeV-iKxZ8YCMaTM933uYvOIHV8xr726pu7dkHQlwCE1Y_EoKpcShlwqxi_aem_XhDFX2ULw8TSZOxILnCAzA If anyone can help. if you are on FRUIT EMU. i for the life of me cant get on as cant register its calling me spam lol and saying im not welcome very odd as i was offering to pay anually. im not the only one who cant so ever runs it may want to look into it. I need this DX LAYOUT and early v ROMS (basically this link downloaded and emailed if poss to me or is it here on the mecca????? its TOP GEAR and this one seems to be the 3 pound version . i have the real machine but its the 4 pound. i love my machine and wanted to see the differences thanks and regards j sharpe showreels4u@hotmail.com

I have used a resistor before and it worked fine but less volume, if he is getting hiss I guess the speaker coil is fine, maybe ohm check the speaker or put a couple of volts across it

These speakers are practically impossible to find unless you are lucky enough to find a "new old stock " speaker or a second hand one . Bob isn't there a way to create 30ohms on a speaker with less ohms using resistors ?

Wow! Just seen this. What an absolute gem of a machine. Good luck - would be lovely to see the old girl in action.

As they say... the end justifies the means.

No, the congratulations are for you, the experts. I'll try to find the right diagram. Thank you. To be continued.

There are three different types of RESET circuit. There is pic of them in the downloads area somewhere and they are all different. Felicitations Lamiral.

You'll tell me; look at your first repaired MPU. !!! Make some comparisons. It's back in its machine and working perfectly thanks to you. I don't want to touch it anymore. Okay, I'm going to investigate my problems. Thanks

T56 should be a thyristor? 2N5061 or 2N5060 at least that's what should have been removed. You had better check!

Good evening, everyone. Thank you for taking an interest in my problem. So, T56 = BC172 (new) As are T57, T58, T59, and T60 (BC172) (new) T61 = ZTX510 (new) I'm going to do some checks, track checks and others. Thanks; have a good evening.

Good Morning, Reset line is on pin 34 of all the 6821`s and a few other places, also easier is the test pin above the power socket, see pic. Connect your logic probe, turn it on and report back what happens. 👍