Search found 1333 matches
- Thu Aug 07, 2014 12:59 am
- Forum: Hardware and Tech
- Topic: Recommend a cheap EPROM programmer?
- Replies: 6
- Views: 2290
Re: Recommend a cheap EPROM programmer?
Thanks, I hadn't come across that model. It's more than twice the price of the Chinese ones, not sure I want to splash out that much.
- Wed Aug 06, 2014 12:11 pm
- Forum: General Topics
- Topic: July OS report
- Replies: 8
- Views: 1959
Re: July OS report
In a long-time Linux user, c. 15 years. I've used it for my work environment for nearly all that time, the few times I have ventured into the world of Windows I wonder how anyone can use it.
- Sat Aug 02, 2014 4:06 am
- Forum: Hardware and Tech
- Topic: Recommend a cheap EPROM programmer?
- Replies: 6
- Views: 2290
Re: Recommend a cheap EPROM programmer?
Thanks for the feedback on the Willem.
I think I'm going to go for a TOP853, I've found one in stock in the UK can it claims to be able to handle 25v devices like the TMS2564.
I think I'm going to go for a TOP853, I've found one in stock in the UK can it claims to be able to handle 25v devices like the TMS2564.
- Tue Jul 29, 2014 11:58 am
- Forum: Hardware and Tech
- Topic: Recommend a cheap EPROM programmer?
- Replies: 6
- Views: 2290
Recommend a cheap EPROM programmer?
I'm thinking of getting a programmer to use for a couple of projects. I must be able to program 27C128 (EPROM) 28C256 (EEPROM) and it would be nice to test RAM, other ICs There seem to be a few programmers about Willem TOP853 G540 Does anyone have any advice on choosing one? Thanks.
- Sun Jul 13, 2014 8:23 am
- Forum: Hardware and Tech
- Topic: My mod from yesteryear
- Replies: 13
- Views: 2869
Re: My mod from yesteryear
Yes, I'm intending to use a 74LS175 as a write-only register to manage bank switching so it's all controlled by software.
My first experiments didn't quite work out so I'm going to have to spend so more time debugging this. I'll post a schematic once I think I have something that works.
My first experiments didn't quite work out so I'm going to have to spend so more time debugging this. I'll post a schematic once I think I have something that works.
- Sat Jul 12, 2014 1:43 am
- Forum: Hardware and Tech
- Topic: 8K Expansion pack
- Replies: 4
- Views: 815
Re: 8K Expansion pack
I would guess one of the RAM chips is faulty. The expansion pack probably consists of 4 x 2K SRAM so 3584 - Internal memory 5632 - +2K 7680 - +4K 9728 - +6K 11776 - +8K as 8786 is less then 9728 I would think the third SRAM is faulty. The KERNAL routine scans through memory until a write/read test f...
- Mon Jul 07, 2014 2:40 pm
- Forum: Hardware and Tech
- Topic: Expansion prototyping boards?
- Replies: 2
- Views: 572
Re: Expansion prototyping boards?
That would do. Anyone in Europe stock these?
- Mon Jul 07, 2014 12:56 pm
- Forum: Hardware and Tech
- Topic: Expansion prototyping boards?
- Replies: 2
- Views: 572
Expansion prototyping boards?
I'd like to start tinkering again and build a few projects. Does anyone know of anywhere to get hold of boards like this old Radio Shack one these days?
- Sun Jul 06, 2014 12:19 am
- Forum: Hardware and Tech
- Topic: My mod from yesteryear
- Replies: 13
- Views: 2869
Re: My mod from yesteryear
Did that, too. The thing about RAM under ROM is to arrange the banking circuitry so that the RAM can be written without switching out the ROM. That way, the ROM can be copied to RAM by PEEK/POKE (or LDA/STA) the same addresses, then modified before making the switch. This would apply to BASIC and K...
- Sat Jul 05, 2014 2:03 pm
- Forum: Hardware and Tech
- Topic: Reviving a dead 1541
- Replies: 24
- Views: 3384
Re: Reviving a dead 1541
Success! I've just replaced UC7 (74LS00) and the drive now powers up and I can read the directory off a disk.
There's something to be said for hardware that so straightforward to repair. They don't make them like that any more.
There's something to be said for hardware that so straightforward to repair. They don't make them like that any more.
- Thu Jul 03, 2014 3:21 pm
- Forum: Hardware and Tech
- Topic: Reviving a dead 1541
- Replies: 24
- Views: 3384
Re: Reviving a dead 1541
The drive spindle is definitely turning and the belt tension seems fine. I've found a list of chips to check on one of Ray's comp.sys.cbm postings UA1 - 74LS14 UB4 - ROM UC2 - VIA UC4 - 6502 UC6 - 74LS04 UC7 - 74LS00 UD3 - 75LS86 UD5 - 74177 I've checked/replaced the first four, I'll work my way thr...
- Wed Jul 02, 2014 2:18 pm
- Forum: Hardware and Tech
- Topic: Reviving a dead 1541
- Replies: 24
- Views: 3384
Re: Reviving a dead 1541
Yes. Symptoms are
On first power up red and green LEDs come on. Drive motor also on. After a while red LED goes out but drive motor still spins.
Subsequent power cycles, LEDs and motor come on, all stay on.
On first power up red and green LEDs come on. Drive motor also on. After a while red LED goes out but drive motor still spins.
Subsequent power cycles, LEDs and motor come on, all stay on.
- Wed Jul 02, 2014 1:39 pm
- Forum: Hardware and Tech
- Topic: Reviving a dead 1541
- Replies: 24
- Views: 3384
Re: Reviving a dead 1541
Well, I've replaced both UA1 and UD2 and the symptoms are the same. In summary I've checked the output voltages of both rectifiers The 5v rail reads 4.93v I've tested the 6502 and both VIAs in my VIC I've dumped the contents of both ROMs and the md5sums match images I've downloaded I've replaced UA1...
- Mon Jun 30, 2014 2:59 pm
- Forum: Programming
- Topic: Closing an RS-232 channel
- Replies: 2
- Views: 1547
Re: Closing an RS-232 channel
Ah, thanks. That's the sort of test I expected. I'll update my ROM dump program to use this.
- Mon Jun 30, 2014 12:59 pm
- Forum: Programming
- Topic: Closing an RS-232 channel
- Replies: 2
- Views: 1547
Closing an RS-232 channel
I've recently been rediscovering the various subtle ways of RS-232 connections (like using >=128 for the LFN to get CRLF at the end of a line). One thing I'm still struggling with is checking the transmit queue is empty before closing the channel. The Programmer's Reference Guide says Care should be...