Search found 1237 matches

by Chandler
Fri Jun 07, 2019 7:59 pm
Forum: For sale / Wanted
Topic: TT internal metal square speaker housing
Replies: 3
Views: 430

Re: TT internal metal square speaker housing

Yes that's it

I have sent you a PM
by Chandler
Fri Jun 07, 2019 1:46 pm
Forum: For sale / Wanted
Topic: TT internal metal square speaker housing
Replies: 3
Views: 430

TT internal metal square speaker housing

I've been slowly restoring a TT for ages and i'm missing just 1 part The small square metal box that the internal speaker fits into it sits ontop of the VME metal housing I know it's not much used for anything the speaker but i'm just trying to keep it all original I have the speaker, i just need th...
by Chandler
Thu May 09, 2019 8:47 pm
Forum: Professionals
Topic: Scope needed for fault finding - any advice on which type?
Replies: 0
Views: 416

Scope needed for fault finding - any advice on which type?

I'm looking for a scope to try and diagnose a dead Falcon

I'm just looking for something simple and basic, portable with simple LCD type screen (if such a thing exists)

Can anyone advise or recommend anything?

:)
by Chandler
Wed May 08, 2019 6:13 pm
Forum: For sale / Wanted
Topic: [Wanted] Q and W keys (old style) for 520ST+
Replies: 2
Views: 581

Re: [Wanted] Q and W keys (old style) for 520ST+

I have this keyboard with one key missing (the "0" on the numeric keypad)

So you can either have the 2 keys you need for £5 each or make me a sensible offer for the whole keyboard? :)
by Chandler
Wed May 01, 2019 8:18 am
Forum: Hardware
Topic: ST520FM screen garbage
Replies: 7
Views: 685

Re: ST520FM screen garbage

The TOS chips are correct, forget the label It's the notch in the middle of one end of the chip that is the important part I would turn off bank 2 of the memory (the upgraded part) and then test again If it still does the black square then it is either the MMU chip / the MMU socket / the ram or the ...
by Chandler
Sat Apr 27, 2019 5:13 pm
Forum: Hardware
Topic: ST520FM screen garbage
Replies: 7
Views: 685

Re: ST520FM screen garbage

Funnily enough i have just repaired a Mega ST with the same screen (black square with lines / white border) It's a memory problem I can see from your motherboard picture that someone has added 512K to make your machine 1mb at some point so maybe the issue could be there I'd check all the solders on ...
by Chandler
Sat Apr 27, 2019 2:21 pm
Forum: Hardware
Topic: TT can't read floppy disks properly and ram problem
Replies: 0
Views: 480

TT can't read floppy disks properly and ram problem

Been working on this early TT motherboard which i originally got non working, so far i now have it going to desktop :) I have 2 problems with it i am trying to solve 1: It won't read floppy disks properly, sometimes it will read the contents of the disks but only shows some of the files and when you...
by Chandler
Thu Feb 07, 2019 8:42 pm
Forum: Professionals
Topic: Dead Falcon - no boot / coloured screen only
Replies: 38
Views: 4254

Re: Dead Falcon - no boot / coloured screen only

OK thanks for your replies guys

I'm going to have a think and maybe get someone to have a look at it before removing Combels without knowing for sure it's that
by Chandler
Thu Feb 07, 2019 8:40 pm
Forum: Hardware
Topic: Mega STE - almost working - NO FDD
Replies: 2
Views: 585

Re: Mega STE - almost working - NO FDD

Thanks! funnily enough i was going to change that chip next, thought i'd just here first in case there was anything else i'd missed

Anyway, great news, changed the chip and now it works perfectly - very pleased!
by Chandler
Wed Feb 06, 2019 9:05 pm
Forum: Hardware
Topic: Mega STE - almost working - NO FDD
Replies: 2
Views: 585

Mega STE - almost working - NO FDD

Been working on this Mega STE for a while as it had a lot of corroded sockets which i have changed So far it now boots with the white screen and Atari logo in left corner, does the memory test ok Then when it is about to go to the desktop i get 4 x bombs There is NO floppy drive activity at all, not...
by Chandler
Wed Feb 06, 2019 8:55 pm
Forum: Professionals
Topic: Dead Falcon - no boot / coloured screen only
Replies: 38
Views: 4254

Re: Dead Falcon - no boot / coloured screen only

What's the easiest way to remove a Combel?
by Chandler
Tue Feb 05, 2019 10:30 am
Forum: Professionals
Topic: Dead Falcon - no boot / coloured screen only
Replies: 38
Views: 4254

Re: Dead Falcon - no boot / coloured screen only

It's a factory board, totally untouched

Well, i do have a Combel IC

The BIG question is do i just remove the old one and fit the new one? it's a big job and not something i'd want to do unless i knew it was the Combel for sure :|
by Chandler
Mon Feb 04, 2019 9:16 pm
Forum: Professionals
Topic: Dead Falcon - no boot / coloured screen only
Replies: 38
Views: 4254

Re: Dead Falcon - no boot / coloured screen only

OK well i have changed the Y3 crystal in the Falcon for a known working one and no change

I should note that the faulty screen appears immediately when switched on and not after a few seconds or after any boot time
by Chandler
Sat Feb 02, 2019 12:09 pm
Forum: Professionals
Topic: Dead Falcon - no boot / coloured screen only
Replies: 38
Views: 4254

Re: Dead Falcon - no boot / coloured screen only

I do want to change the Y3 crystal on the Falcon it's a 32.08498MHz I have since found out it is also used in the PAL STE and Mega STE Well there is a 2 pin crystal in the same package with the same number on it to the left of the STE motherboard, different Atari part number but identical crystal nu...
by Chandler
Wed Jan 30, 2019 9:57 am
Forum: Professionals
Topic: Dead Falcon - no boot / coloured screen only
Replies: 38
Views: 4254

Re: Dead Falcon - no boot / coloured screen only

Regarding the 32.08498MHz crystal

I have since found out it is also used in the PAL STE and Mega STE

Well there is a 2 pin crystal in the same package with the same number on it to the left of the motherboard

So, would this work in the Falcon?
by Chandler
Fri Jan 18, 2019 6:54 pm
Forum: Professionals
Topic: Dead Falcon - no boot / coloured screen only
Replies: 38
Views: 4254

Re: Dead Falcon - no boot / coloured screen only

Can anyone advise a basic scope for testing things like this? will a cheap LCD type do it?
by Chandler
Thu Jan 17, 2019 10:37 pm
Forum: Hardware
Topic: SM 124 black screen BUT power LED ok and sound
Replies: 18
Views: 2014

Re: SM 124 black screen BUT power LED ok and sound

Yes i have the MT-21 type, just downloaded the correct manual

Page 7 and 8 are quite useful and shows that the power supply should give out 12V and 27V

I'm sure the 12V is ok due to LED and sound, but not checked the 27V ..
by Chandler
Thu Jan 17, 2019 9:39 pm
Forum: Professionals
Topic: Dead Falcon - no boot / coloured screen only
Replies: 38
Views: 4254

Re: Dead Falcon - no boot / coloured screen only

OK on my mobo it's a 2 pin package on Y3

Any idea where i can get some of these? i'd rather get the exact part: 32.08498MHz
by Chandler
Thu Jan 17, 2019 10:21 am
Forum: Hardware
Topic: SM 124 black screen BUT power LED ok and sound
Replies: 18
Views: 2014

Re: SM 124 black screen BUT power LED ok and sound

Thanks for your reply I have no scope I should mention too that there are 2 types of SM 124, both look the same outside but are totally different inside The early type has the power supply on the left side of the monitor with a large transformer The later type has the power supply built into the mai...
by Chandler
Tue Jan 15, 2019 8:11 pm
Forum: Hardware
Topic: SM 124 black screen BUT power LED ok and sound
Replies: 18
Views: 2014

Re: SM 124 black screen BUT power LED ok and sound

Totally lost with this one

To be honest the service manual for these is pretty useless, done all the tests it suggests and nothing
by Chandler
Tue Jan 15, 2019 8:09 pm
Forum: For sale / Wanted
Topic: Falcon CPU - Where to buy?
Replies: 5
Views: 956

Falcon CPU - Where to buy?

I'm looking for a Falcon CPU and will gladly take 2 or 3

Does anyone know where these can be sourced for a good price?

Wasn't the CPU a bit specific to the Falcon? or is it just a standard Motorola chip?

:)
by Chandler
Tue Jan 15, 2019 11:57 am
Forum: Professionals
Topic: Dead Falcon - no boot / coloured screen only
Replies: 38
Views: 4254

Re: Dead Falcon - no boot / coloured screen only

Which Oscillator is the master clock? there are 2 oscillators on the board

1 in the middle next to the large capacitor and the other next to the DSP chip
by Chandler
Sun Jan 13, 2019 11:28 pm
Forum: Professionals
Topic: Dead Falcon - no boot / coloured screen only
Replies: 38
Views: 4254

Re: Dead Falcon - no boot / coloured screen only

I have changed the ram to a known working 4mb factor type

new NVRAM chip works in another Falcon (along with the memory card)
by Chandler
Sun Jan 13, 2019 8:00 pm
Forum: Professionals
Topic: Dead Falcon - no boot / coloured screen only
Replies: 38
Views: 4254

Re: Dead Falcon - no boot / coloured screen only

Yes screen is same after a few resets

Yes PSU is fine (as used in a working Falcon)

I have no test equipement other than a logic probe (what do i need)

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