I've got a floppy drive belt on the list and watched afew videos on Youtube about changing it.p13z wrote: ↑Thu Jul 15, 2021 7:24 pm A +3 will typically be in good condition. A clean around the keyboard while you have things apart is often a good idea.
If the floppy drive belt hasn't ever been changed - it will need to be, an original will have perished badly by now.
Other than that - they are pretty robust machines.
The power supplies can suffer from broken connections / tracks if they have been kicked around a lot over the years.
The video / audio quality on these machines is considered broken from new by a lot of folk - so some people like to mod that side of things, but personally I kind of like the nostalgia of a fuzzy +3.
Good luck.
How much you after for your one?spider wrote: ↑Thu Jul 15, 2021 7:38 pm Could of had mine cheaply with either internal 3" or 3.5" :p
On an on topic note, congrats on your recent ebay purchase.
I agree about the drivebelt tend to perish with age and if it gums the pulley its a pain to clean them out.
Be aware its dead easy to lose the tiny 'pin' on these. I'd recommend checking the guides out before attempting the belt. It is quite easy though, no special tools needed just need to be aware not to turn the drive over when its "all loose"
There's a few guides about about this, here's one that has a few pics etc.
The floating bus mod might be worth considering maybe (I can't recall offhand but it involves one component on the solder side iirc) can improve some 48K game compatibility. For what is worth I've not bothered doing my machines yet though.
The distorted audio was pretty much the first thing that came up when I started searching..MrClump wrote: ↑Fri Jul 16, 2021 8:53 am The audio is badly distorted on a lot of earlier +3s due to a design flaw, so long as your not too ham-fisted with a soldering iron it’s pretty easy to resolve. Details of the mod can be found at:
https://spectrumforeveryone.com/technic ... pectrum-3/
In fact there a few +3 mods detailed on SFE, it’s worth a read.
but it may well work.
It is a single resistor. It allows the Z80 to read a value on the data bus on a +3, +2A or +2B in a similar way that is normal on the earlier ZX Spectrum models. It only works for some games. And is not needed for the majority of games.
Standby alert 
: 1 x 470 Ω resistor and two short lengths of (insulated please) wire. I guess it could be done component side but I've not checked that. According to the linked page connect said resistance between pins 17 of IC4 and IC6 Ah yep, remember seeing that while looking through various search results.
Yep, came across that while searching... I'll leave it for now though...spider wrote: ↑Wed Jul 21, 2021 4:14 pm Thanks @1024MAK , I mix up 'tech' floating bus vs point , thankfully I don't mix those terms in real life!
Do realise that you're right its not going to 'help everything' but I guess there's no harm in doing it -if- the Speccy is already in bits, ie PCB is out.
The article I mentioned is here , there's probably another or two floating about too.
Simples™
Disclaimer : I've not tried this myself yet!
Most likely. Ideally, though, you’ll want to switch your TV to accept the RGB signal manually. Some TVs allow you to do that either via a menu or via a dedicated button on the remote.Speccy_Pete wrote: ↑Thu Jul 22, 2021 8:33 pm Any chance doing the R44 fix for the 12v at the RGB socket is going to fix this?
That’s the ‘classic’ image you get when the TV/display is ignoring the RGB signal and instead trying to display a composite video signal (where there is only sync information plus a little bit of ‘leakage’ of some picture information).Speccy_Pete wrote: ↑Thu Jul 22, 2021 8:33 pm And...
Nooooooo...
Somethings not happy...
Any chance doing the R44 fix for the 12v at the RGB socket is going to fix this?
Standby alert It's completely auto no maual override/selection available, Which sucks!Ast A. Moore wrote: ↑Thu Jul 22, 2021 10:32 pm Most likely. Ideally, though, you’ll want to switch your TV to accept the RGB signal manually. Some TVs allow you to do that either via a menu or via a dedicated button on the remote.
No manual selection option on this TV unfortunately.1024MAK wrote: ↑Thu Jul 22, 2021 11:16 pm That’s the ‘classic’ image you get when the TV/display is ignoring the RGB signal and instead trying to display a composite video signal (where there is only sync information plus a little bit of ‘leakage’ of some picture information).
If your TV/display has a manual input selection, use that. Otherwise the correct voltages need to go to SCART plug pins 8 and 16.
Either modify the ZX Spectrum +3 and check how the SCART lead is wired, or use an another (external) PSU to provide +12V.
Mark
Standby alert The RCS scart cable (link I posted) only shows +12v connected to pin 16 with a 220uf electro cap between pin 16 and 18...1024MAK wrote: ↑Fri Jul 23, 2021 3:27 am Yep, RetroComputerShack cables are very good. I use them myself
But no cable on it’s own can fix the strange design decision to use a 1kΩ (R44) resistor in series with the +12V supply
Incidentally, though the Spectrum For Everyone site gives the resistor values you quoted, the actual value is not critical. Myself, I would be happy with replacing R44 with any value between 120Ω and 220Ω (or piggy backing a 150Ω to 270Ω ). In the SCART plug, the +12V goes directly to pin 8. Then solder a 220Ω resistor between pin 8 and pin 16. This should then feed the correct voltages to pins 8 and 16 so that the TV/display switches to RGB input mode.
Mark
If you leave R44 alone, the current is limited to too low a value, hence pin 16 (which has an input impedance of about 75Ω) will not get enough voltage (*). So the TV may stay in composite video modeSpeccy_Pete wrote: ↑Fri Jul 23, 2021 5:30 am Not a good idea to leave R44 alone and bridge Pin 8 and 16 with 220ohm (+75) = 2.734v in the plug without causing any damage or letting the magic smoke escape?
Standby alert Doh, I only added the two... 220+75... completely forgot about the 1000... oh dear!1024MAK wrote: ↑Fri Jul 23, 2021 8:53 amIf you leave R44 alone, the current is limited to too low a value, hence pin 16 (which has an input impedance of about 75Ω) will not get enough voltage (*). So the TV may stay in composite video modeSpeccy_Pete wrote: ↑Fri Jul 23, 2021 5:30 am Not a good idea to leave R44 alone and bridge Pin 8 and 16 with 220ohm (+75) = 2.734v in the plug without causing any damage or letting the magic smoke escape?
(*) the calculation is 12/(1000+220+75)x75=0.695V
Mark
