Very odd for JLCPCB to mess up like that, they're normally flawless in my experience. Put it down to an aberration at their end.
Search found 684 matches
- Fri May 03, 2024 8:39 am
- Forum: Hardware
- Topic: Pico based Spectrum ROM interface (photoessay)
- Replies: 37
- Views: 1553
- Fri Apr 26, 2024 4:27 pm
- Forum: Hardware
- Topic: DC-DC mod query
- Replies: 6
- Views: 349
Re: DC-DC mod query
To complete the story, in case anyone finds it in a search, I got the DC circuit working. I desoldered the cluster of components, then rejoined them all spread out so I could get access to those underneath. I then printed out the circuit shown here , and went through it point by point, ticking off e...
- Sun Apr 21, 2024 11:26 am
- Forum: Games/Software
- Topic: Jetpac to Microdrive
- Replies: 25
- Views: 1025
Re: Jetpac to Microdrive
There's a remarkably in depth discussion of this exact question from about a year ago here.Redgatemodels wrote: ↑Sun Apr 21, 2024 10:16 am Hi, I guess this is a rookie question, but I am trying to get Jetpac onto microdrive and have failed.
Can it be done?
- Fri Apr 19, 2024 8:16 pm
- Forum: Programming
- Topic: Goodbye,Z80
- Replies: 33
- Views: 1723
- Thu Apr 18, 2024 3:48 pm
- Forum: Hardware
- Topic: DC-DC mod query
- Replies: 6
- Views: 349
Re: DC-DC mod query
I know it's hard to tell, but if TR4 is getting hot, one of the 4116 (or equivalent) "lower" DRAM chips may have failed and is now drawing excessive current. Hence dragging the +12V rail down. I'll have a closer look at your photo later when I'm on a PC. This is the current working versio...
- Thu Apr 18, 2024 3:34 pm
- Forum: Hardware
- Topic: DC-DC mod query
- Replies: 6
- Views: 349
Re: DC-DC mod query
The website/blog you linked to is mine BTW. Yes, I thought so. Thanks for doing that. I wanted to tell you that the schematic has two D15 diodes on it, which has rather puzzled me. I think one of them is actually the new D17 which is one of my green dotted diodes in my image? I was also a bit puzzl...
- Thu Apr 18, 2024 12:17 pm
- Forum: Hardware
- Topic: DC-DC mod query
- Replies: 6
- Views: 349
Re: DC-DC mod query
That's an excellent video, but his final work doesn't look much like the board I have!
I'm still working on it...
I'm still working on it...
- Thu Apr 11, 2024 6:13 pm
- Forum: Hardware
- Topic: DC-DC mod query
- Replies: 6
- Views: 349
DC-DC mod query
I have an issue 3 board which has a faulty 12V supply (reads a wobbly +1.2V). -5V works correctly. I've never tried to fix a DC-DC problem before, so I thought I'd start from first principles. The board has had a DC-DC mod of some sort, so I've had a good look at it and taken notes. Here's an annota...
- Wed Apr 03, 2024 9:42 am
- Forum: Hardware
- Topic: Hardware diagnostics interface (Pico based)
- Replies: 4
- Views: 222
Re: Hardware diagnostics interface (Pico based)
Oh, and during the RAM check that the ROM does, it may be possible to check for some RAM faults that the ROM code does not test for. It's not possible to pick up all RAM faults, because the intention of the ROM routine is to simply work out how much RAM is fitted, NOT if it works correctly. Hence t...
- Wed Apr 03, 2024 9:36 am
- Forum: Hardware
- Topic: Hardware diagnostics interface (Pico based)
- Replies: 4
- Views: 222
Re: Hardware diagnostics interface (Pico based)
The next step would be an instruction trace, Often knowing at what point the Z80 is no longer executing the expected sequence can help identify the problem, or at least narrow it down. If there is no input from the user, the machine should make it to the "copyright" screen with the only v...
- Tue Apr 02, 2024 8:13 pm
- Forum: Hardware
- Topic: Hardware diagnostics interface (Pico based)
- Replies: 4
- Views: 222
Hardware diagnostics interface (Pico based)
Whenever someone pops up asking for help with a broken Spectrum, the initial investigation asked of them is always the same: measure the voltages, tell us what test equipment you have, then do some initial signal checks based on what they can do with the equipment they have to hand. Would it not be ...
- Sat Mar 09, 2024 9:55 am
- Forum: Sinclair Miscellaneous
- Topic: Sinclair QL Design issues
- Replies: 30
- Views: 1228
Re: Sinclair QL Design issues
If the QL had looked like Rick Dickinson's redefinition, it could have had the mechanism from a clockwork mouse inside it and it still would have flown off the shelves.
- Wed Feb 28, 2024 4:45 pm
- Forum: Emulators
- Topic: ZEsarUX 11 Beta
- Replies: 8
- Views: 567
Re: ZEsarUX 11 Beta
I found it complicated and confusing. Sarcastically dismiss the feedback if you like.chernandezba wrote: ↑Wed Feb 28, 2024 3:05 pm 2 Menus. "several screens" is exaggerated
...
Nothing further your honor
- Wed Feb 28, 2024 2:46 pm
- Forum: Emulators
- Topic: ZEsarUX 11 Beta
- Replies: 8
- Views: 567
Re: ZEsarUX 11 Beta
I think you are exaggerating Are you really serious it’s difficult to get to the menu save screen? :oops: I'm not exaggerating. That STL screenshot took me about 10 minutes to make. Getting to the menu isn't difficult. Getting a screenshot of what I wanted proved very difficult. The problem is that...
- Wed Feb 28, 2024 2:05 pm
- Forum: Hardware
- Topic: New open lower RAM module design (photoessay)
- Replies: 98
- Views: 3564
Re: New open lower RAM module design (photoessay)
However, I think it should be possible to develop the module on a two-layer PCB, and the price difference here is significant. Earlier in the thread you said the price difference at JLCPCB between an order for 2 layer boards and 4 layer boards is about $5. Here in the UK that's less than the cost o...
- Wed Feb 28, 2024 12:20 pm
- Forum: Emulators
- Topic: ZEsarUX 11 Beta
- Replies: 8
- Views: 567
- Thu Feb 22, 2024 10:14 am
- Forum: Showcase your work!
- Topic: Replacement Case for Interface 1
- Replies: 5
- Views: 570
Re: Replacement Case for Interface 1
That's a really nice piece of work, Tom, great job. I was thinking about making something similar to house my recreated ZX Spectrum Expansion System project, but there was a problem I couldn't see an easy answer to: the PCB for a project which is housed in such a case obviously needs an edge connect...
- Thu Feb 22, 2024 10:01 am
- Forum: Hardware
- Topic: Recap Problem.
- Replies: 5
- Views: 558
Re: Recap Problem.
You wait until you get tin whiskers. Then you'll be puzzled.
- Fri Feb 16, 2024 10:49 am
- Forum: Sinclair Miscellaneous
- Topic: Who do you buy your spare parts from
- Replies: 8
- Views: 707
Re: Who do you buy your spare parts from
They say that you can pay through paypal with a credit card if you log in as guest but I just cant see that option on my screen I'm pretty sure it means logging into Paypal as a guest. i.e. you don't need a Paypal account. So make your order at Retroleum, click to pay via Paypal, when the Paypal wi...
- Mon Feb 12, 2024 1:40 pm
- Forum: Programming
- Topic: Beating the C compiler...
- Replies: 22
- Views: 1044
Re: Beating the C compiler...
Ah right, I suspected people were doing this unrolled. It just eats in to the RAM, but I think I've got enough space left, plus I can move some of the non-in game graphics in to low RAM. I can probably free up 2kb or so, and I'll give this a go... here is where I find out this is exactly how the co...
- Sun Feb 11, 2024 8:55 pm
- Forum: Hardware
- Topic: Cant load anything
- Replies: 41
- Views: 1618
Re: Cant load anything
Hurrah!
OK, power up into BASIC and try
Code: Select all
BEEP 1,0
- Sun Feb 11, 2024 8:35 pm
- Forum: Hardware
- Topic: Cant load anything
- Replies: 41
- Views: 1618
Re: Cant load anything
i dont think its volume ... im thinking it is a hardware issue - would old failing caps possibly effect the signal going into the machine Here's another thread on the topic on another site. Here's another . It isn't out of the question that a capacitor is causing a problem, there's a bit of filteri...
- Sun Feb 11, 2024 8:22 pm
- Forum: Hardware
- Topic: Cant load anything
- Replies: 41
- Views: 1618
Re: Cant load anything
Are you supposed to hear the noise of software loading from the spectrums internal speaker during loading ? Yes! The tape loader screeching noise is absolutely characteristic of the machine and you should be able to hear it as the tape loads. If you're not hearing that, you're missing out. So is th...
- Sun Feb 11, 2024 8:13 pm
- Forum: Hardware
- Topic: Cant load anything
- Replies: 41
- Views: 1618
Re: Cant load anything
There's a bit of information in this thread about volume and amplification and the options open to you. Probably other threads as well if you search the archives, it's quite a common subject. If you want to investigate your apparent upper memory issue I suggest you start a new thread with a suitable...
- Sun Feb 11, 2024 8:03 am
- Forum: Hardware
- Topic: Cant load anything
- Replies: 41
- Views: 1618
Re: Cant load anything
Your machine is a 48K, the DRAM slots in the lower right are all populated. It sounds like it was sold to you as a 16K because the upper RAM isn't working? You might still be able to load a 16K game, though. What device are you using to play the tape? Spectrums require significant volume from the ta...