Search found 358 matches: +electron +circuit

Searched query: +electron +circuit

by 1024MAK
Tue Jan 15, 2019 11:52 pm
Forum: hardware
Topic: Preemptive maintenance
Replies: 16
Views: 392

Re: Preemptive maintenance

... only cosmetic stuff. I have other vintage 8 bit computers (a very clean Electron and tape drive, and a nice Spectrum+) and there seems to be no real ... is because of the internal DC/DC switch mode converter/inverter circuit. This converts the nominal 9V DC input to a +12V and more importantly, ...
by rmbrowngr
Mon Dec 31, 2018 3:47 pm
Forum: hardware
Topic: Electron IC18 & IC17
Replies: 4
Views: 216

Electron IC18 & IC17

I hadmy Elk Open today to repair yet another key and took a look at the circuit board. I see that the spaces for IC17 & IC18 are empty. What were these intended for?
by daveejhitchins
Mon Dec 24, 2018 9:10 am
Forum: hardware
Topic: New Design For Electron Disc Interface AP3/4/Peg - Now Progressing (23-12-2018)
Replies: 21
Views: 1566

Re: New Design For Electron Disc Interface AP3/4/Peg - Now Progressing (23-12-2018)

... link Mark Thanks, Mark, for reminding me of those parts, however, I would probably use another PLD to get what's needed as I could also add the ÷2 circuit in there along with the extra memory decoding. I may have to start the layout to see how the space pans out. Dave H :D
by daveejhitchins
Sun Dec 02, 2018 5:46 pm
Forum: hardware
Topic: Loss of output on Electron RGB Port
Replies: 24
Views: 503

Re: Loss of output on Electron RGB Port

1024MAK wrote:
Sun Dec 02, 2018 5:43 pm
By default, both the BBC B and the Electron only output a monochrome (black and white) video signal on the composite video outputs.
yell0w_lantern wrote:
Sat Dec 01, 2018 5:08 am
Acorn Electron +1 with color mod
Without a 'scope it may be a case of replacing each IC in the colour generating circuit one at a time :?

Dave H :D
by daveejhitchins
Sat Dec 01, 2018 7:34 am
Forum: hardware
Topic: Loss of output on Electron RGB Port
Replies: 24
Views: 503

Re: Loss of output on Electron RGB Port

Acorn Electron +1 with color mod Composite video out works but RGB has stopped working. I'm running ... on RGB and composite outputs.The colour burst is generated from the ULA via the circuit around part of IC12 (at the bottom of the attached schematic clip). Do you have any ...
by SimonSideburns
Mon Nov 19, 2018 8:52 pm
Forum: other vintage computer hardware, software and games
Topic: Vintage Collections
Replies: 49
Views: 1401

Re: Vintage Collections

... with it much at all. It works really well with a CUB monitor. Acorn Electron. Came with a busted ULA and I was helped out on stardot to get it ... to help me by cutting out the Dallas chip and maybe caught the circuit board with the dremel, and it's been sat in the loft in bits ever ...
by 1024MAK
Sat Nov 17, 2018 1:25 pm
Forum: hardware
Topic: Electron Data Recorder ?
Replies: 16
Views: 353

Re: Electron Data Recorder ?

... FROM the cassette deck Pins 4 & 5 - No connection needed (they are for use with stereo audio systems) Pins 6 & 7 - Two wires for the motor control circuit Acorn Application note giving connector pin-out details Mark
by 1024MAK
Sat Nov 17, 2018 1:23 am
Forum: hardware
Topic: Electron Data Recorder ?
Replies: 16
Views: 353

Re: Electron Data Recorder ?

... use two pins for audio in, two for audio out, and one for screen/GND. The two extra pins on the 7 pin DIN are used for the motor control circuit. Mark
by elkrepair
Thu Nov 15, 2018 8:09 pm
Forum: hardware
Topic: New caps for an Electron
Replies: 5
Views: 207

New caps for an Electron

Hi. According to the circuit diagram, the main PCB for the electron should have the following electrolytic capacitors: C1: 47uF 16v C2: 10uF 16v C7: 10uF 35v C11: 10uF ...
by BeebMan2018
Sat Nov 10, 2018 1:58 am
Forum: hardware
Topic: Electron Sound Issue, Fault or Ignorance ?
Replies: 5
Views: 168

Re: Electron Sound Issue, Fault or Ignorance ?

... ? I could turn out new ones on a lathe but making them is only a small part of it. On one side one of the spacers appear to also form part of the circuit as a trace terminates underneath the spacer/rivet. I'm thinking maybe a ground or something ? I don't want to go diving in there just yet until ...
by Kazzie
Thu Nov 01, 2018 10:45 am
Forum: hardware
Topic: Phillips CM8833 Troubles
Replies: 19
Views: 689

Re: Phillips CM8833 Troubles

I don’t know about this chassis, but if the electron gun current gets to too high a value, a protection circuit will cause a shut down. The less complex protection circuits don’t latch, so the set will then ...
by 1024MAK
Wed Oct 31, 2018 10:39 am
Forum: hardware
Topic: Phillips CM8833 Troubles
Replies: 19
Views: 689

Re: Phillips CM8833 Troubles

I don’t know about this chassis, but if the electron gun current gets to too high a value, a protection circuit will cause a shut down. The less complex protection circuits don’t latch, so the set will then cycle. So how bright is the white screen?

Mark
by BitSeeker
Tue Oct 23, 2018 7:48 pm
Forum: hardware
Topic: Adapting joysticks for the BBC micro
Replies: 25
Views: 1008

Re: Adapting joysticks for the BBC micro

I reverse engineered the Competition Pro (circuit attached). A +5v supply is indeed required via pin 7 with pin 8 providing ... hoping some epoxy resin glue will fix this. I have recently found that on one Electron, full movement through my interface doesn't give quite MAX ADC value, and ...
by gidandridge
Sun Oct 07, 2018 6:17 pm
Forum: hardware
Topic: Electron Cumana Disc Interface
Replies: 5
Views: 275

Electron Cumana Disc Interface

... discovered that in a previous life the Ni-MH battery had leaked and the circuit board had been badly damaged. :( It looks like someone managed to ... as an upgrade. Well I did all that and now it can be detected by the electron, I can run all it's star commands, but the disk drive doesn't respond. ...
by daveejhitchins
Tue Oct 02, 2018 5:03 pm
Forum: general
Topic: Today I received.....
Replies: 4958
Views: 356686

Re: Today I received.....

... Both ABRs have Lithium batteries fitted with the battery charging circuit modified* so no charging could take place. Both batteries measured ... contained ADFS E00 and the older, original version contained the Electron Tube code. I can't remember how many ABRs were fitted with Lithium ...
by Kazzie
Sun Sep 30, 2018 5:51 pm
Forum: hardware
Topic: Phillips CM8833 Troubles
Replies: 19
Views: 689

Re: Phillips CM8833 Troubles

... that my LOPT (HR7506) isn't the exact same as that specified in the circuit diagram I have (HR6489). It seems that the two versions of the CM8833 ... to my eye. The 30V PTP pulse output goes round the RGB elements of the electron gun via two inductors, so it seems reasonable for it to offer no ...
by Kazzie
Sun Sep 30, 2018 9:25 am
Forum: hardware
Topic: Phillips CM8833 Troubles
Replies: 19
Views: 689

Re: Phillips CM8833 Troubles

... to 56 ohms(!) when connected to the main board. Working from the circuit diagram, the 125V supply connects to two points: R469 next to the line output transformer, and through connector M6 to the electron gun's board. Having disconnected M6 the resistance on the 125V output ...
by 1024MAK
Tue Sep 18, 2018 5:54 pm
Forum: projects
Topic: 160 x 128 mode
Replies: 21
Views: 704

Re: 160 x 128 mode

... the EHT voltage from the line output transformer. Most line timebase circuits in CRT TV sets should continue to oscillate at or just under 15625Hz ... over or other high voltage damage. Too low and the operation of the electron gun system will be affected, resulting in the width reducing and ...
by davidb
Tue Sep 11, 2018 9:35 am
Forum: general
Topic: 4corn update 11/09/2017 - 9 more manuals
Replies: 1
Views: 249

Re: 4corn update 11/09/2017 - 9 more manuals

... - Volume 1 - Enormous folder containing technical information and circuit diagrams on Acorn System, Atom, BBC and Electron machine Plus diagrams for many of the add-ons, such as the Z80 and 6502 second processors ...
by flibble
Tue Sep 11, 2018 12:50 am
Forum: general
Topic: 4corn update 11/09/2017 - 9 more manuals
Replies: 1
Views: 249

4corn update 11/09/2017 - 9 more manuals

... - Volume 1 - Enormous folder containing technical information and circuit diagrams on Acorn System, Atom, BBC and Electron machine Acorn R140 RISC iX System Administrator's Guide TCP-IP Protocol Suite - User ...
by 1024MAK
Fri Aug 17, 2018 5:21 pm
Forum: hardware
Topic: Microcitec Cub 452 (Lack of) Display Issue
Replies: 10
Views: 488

Re: Microcitec Cub 452 (Lack of) Display Issue

... would make any difference. I think this fault may be a problem with the electron beam scanning system. It looks like the horizontal scan may be partly ... faults, but this looks most likely. The good news is that the EHT circuit is working, as is the Tube, so this could well be repairable. Mark
by daveejhitchins
Thu Jul 26, 2018 8:17 am
Forum: hardware
Topic: Restoration of Three Cumana Electron Disc Interfaces
Replies: 10
Views: 677

Restoration of Three Cumana Electron Disc Interfaces

I have four Cumana Electron Disc Interfaces . Three belonging to Elk Towers and the fourth belonging to Arcadian. ... . . Dishwasher time :D IMG_2747.jpg IMG_2748.jpg All clean now . . . Time to do some circuit tracing. Dave H :D Edit #1 - Thought I only had 3 - found another - corrected ...
by hicks
Sun Jul 01, 2018 9:34 pm
Forum: hardware
Topic: Electron ULA Schematics
Replies: 45
Views: 3622

Re: Electron ULA Schematics

... value in, yet somehow a "0" _must_ make its way into CDATA on the real Electron as that's the only way the circuit will see a start bit, count to 8 and trigger RX Full (which southern belle relies on ...
by myelin
Fri Jun 29, 2018 9:34 pm
Forum: hardware
Topic: Missing old/new Electron Expansions
Replies: 76
Views: 1834

Re: Missing old/new Electron Expansions

... got me thinking on various threads about what is not about for the Electron, a dredge of previous threads really. - With Daniel's freewifi for ... to bit-bash it on microcontrollers with a relatively simple interface circuit (no LM319 and sea of resistors for collision detection). Adding a ...
by hicks
Wed Jun 27, 2018 11:24 pm
Forum: hardware
Topic: Electron ULA Schematics
Replies: 45
Views: 3622

Re: Electron ULA Schematics

... hold previous data. Re-sync? I'm guessing that the stop/start bit combination with the reset occurring after only half of the stop bit, allows the circuit to re-sync such that the next time the 2 bit counter causes a shift to occur, it's likely timed to occur right in the middle of the 1200Hz pulse. ...
by daveejhitchins
Sat Jun 16, 2018 8:36 am
Forum: hardware
Topic: Electron Plus3 + ROM/RAM board problem
Replies: 13
Views: 554

Re: Electron Plus3 + ROM/RAM board problem

OK - PSU just fine - the number of engineers I've told, over the years "don't measure open circuit e.g. not loaded, supplies - you'd think I'd practice what I preach - D'oh! :oops: Just faulty drive. Ray, I can replace this with the same model of drive or let you play ...
by rharper
Fri Jun 15, 2018 8:47 pm
Forum: hardware
Topic: Electron Plus3 + ROM/RAM board problem
Replies: 13
Views: 554

Re: Electron Plus3 + ROM/RAM board problem

This is where it gets interesting: +5V OK - +12V measures 16V ooooch! Drive is officially dead! Probably just the motor drive circuit - but more of that later. Dave H :D Ah well, I was thinking of having a Plus3 with a modern 3.5 inch drive to make it a 640K unit anyway. I can have some ...
by daveejhitchins
Fri Jun 15, 2018 6:07 pm
Forum: hardware
Topic: Electron Plus3 + ROM/RAM board problem
Replies: 13
Views: 554

Re: Electron Plus3 + ROM/RAM board problem

Received the Electron and Acorn Plus 3 combination today. First look shows that the Drive is not being ... OK - +12V measures 16V ooooch! Drive is officially dead! Probably just the motor drive circuit - but more of that later. Acorn Plus 3 Power Supply Schematic.png What's interesting ...
by myelin
Mon Jun 11, 2018 10:52 pm
Forum: hardware
Topic: Electron unstable/fails to boot when Plus 1 is connected
Replies: 21
Views: 2048

Re: Electron unstable/fails to boot when Plus 1 is connected

... lead both ways around). Good thinking! My meter measured a total open circuit in one direction, and about 7Mohm in the other, so I guess that's ... and there don't seem to be any, whether it's plugged in to the Electron or disconnected. With the Plus 1 disconnected and unpowered, there ...
by jms2
Tue May 22, 2018 4:36 pm
Forum: hardware
Topic: Master Ram Board or Second Processors.
Replies: 4
Views: 481

Re: Master Ram Board or Second Processors.

It's a good question, and one which Electron owners faced back in the 80s. The MRB was the winner back then because it ... This is quite a short list, so if you have a Plus 1 and don't mind bits of circuit board sticking out of your machine I would definitely recommend getting an ...