Search found 32 matches

by Tiger
Wed May 26, 2021 9:01 am
Forum: Hardware
Topic: Bad 12v line ISSUE 6A with only 5v RAM
Replies: 27
Views: 3282

Re: Bad 12v line ISSUE 6A with only 5v RAM

sorry to say that, but without skills in soldering it is very easy to destroy the fine lines between the IC pin's. Most "RAM upgraded" or "ROM replaced" ZX Spectrum's which I bought had this kind of faults. Sockets where soldered and soldering lines under this socket where shortened or broken. :roll...
by Tiger
Thu May 20, 2021 7:03 pm
Forum: Hardware
Topic: TZXduino problem
Replies: 10
Views: 1041

Re: TZXduino problem

Hmm - I remember, that I had also a problem in this kind. There was a problem with the SD-card adapter: one of the lines to the pins (I think it was the "CS" pin) was broken. Best is to test whether all connections on the SD-card pcb are OK. Easiest way is to try an other SD-Card adapter ...
by Tiger
Thu May 20, 2021 9:43 am
Forum: Hardware
Topic: TZXduino problem
Replies: 10
Views: 1041

Re: TZXduino problem

Same problem with all baudrates? The SD-Card is FAT16 or FAT32 formatted (no exFAT or NTFS)? Some microSD cards may not work. Cards up to 32GB may work - I use 8GB cards. Something wrong with the soldering points or IC connector? Try an other SD-Card reader (maybe an CS-Signal fault?).
by Tiger
Mon May 17, 2021 8:36 pm
Forum: Hardware
Topic: TZXduino problem
Replies: 10
Views: 1041

Re: TZXduino problem

Here are some screens I take from my TZXduino ...
by Tiger
Mon May 17, 2021 8:02 pm
Forum: Hardware
Topic: TZXduino problem
Replies: 10
Views: 1041

Re: TZXduino problem

It's not easy to make a diagnostic far from the location where it happens. The files are listet - OK you see a filename, but is it a correct datatype? The displayed filename can also be a directory. If your tzx-file works in an emulator (e.g. Spectaculator) it will work with TZXduino.
by Tiger
Mon May 17, 2021 6:11 pm
Forum: Hardware
Topic: TZXduino problem
Replies: 10
Views: 1041

Re: TZXduino problem

I made some TZXDuino's too. As I can remember I'd trouble with the "old" TZXDuino-master (V1.7b is from 2018). I used the MaxDuino files https://github.com/rcmolina/MaxDuino_v1.67. Version 1.66 is the latest for "Nano" (V.167 has new code for ST32). You have to make some changes in the userconfig.h ...
by Tiger
Mon May 03, 2021 1:13 pm
Forum: Hardware
Topic: Bad 12v line ISSUE 6A with only 5v RAM
Replies: 27
Views: 3282

Re: Bad 12v line ISSUE 6A with only 5v RAM

If you really think it's only a 12V-fault (and not the 1889 itself) I would swap the 7805 with an OKI-78SR-5. In this case you can take a 12V power supply instead of 9V and grab the 12V directly from the "power in" to pin 14 (best use a diode to prevent a shorting if the LM is broken) of the LM1889....
by Tiger
Fri Apr 02, 2021 8:41 pm
Forum: Hardware
Topic: Fault ZX Spectrum 48k
Replies: 5
Views: 770

Re: Fault ZX Spectrum 48k

I also think it is a faulty upper-RAM. ;)
by Tiger
Sun Feb 14, 2021 4:35 pm
Forum: Hardware
Topic: Spectrum 48K Upper Ram Fault
Replies: 22
Views: 2147

Re: Spectrum 48K Upper Ram Fault

Thank you Mark - that's what I meant
by Tiger
Sat Feb 13, 2021 3:30 pm
Forum: Hardware
Topic: Spectrum 48K Upper Ram Fault
Replies: 22
Views: 2147

Re: Spectrum 48K Upper Ram Fault

@hatman72 I think the answer is in the second sentence of point 5 in Table 1: "Provided there is only one faulty ic at the address". I think there is more than one of the IC's out of order so the PEEK's and POKE's are not very helpful. A other problem I've found on some Speccy's are "perfect" solder...