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IC Decap: Texas Instruments TMS57002 Audio DSP

TMS5007 Package
TMS5007 Package

This is an Audio DSP chip from the early 90’s, used for sound effects in audio mixing consoles. Unfortunately I couldn’t find much info on these.

TMS57002 Die
TMS57002 Die

The die is massive, 10mm square at least. Interestingly, the markings on the die indicate it’s a TMS67002, maybe there was a different internal software version for the 57002 with fewer features, that used the same Silicon? In the centre of this die, there’s an area that looks like mask ROM, with the individual memory bits visible.

ROM Closeup
ROM Closeup
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GB3WP & G6YRK – Rant Time

It’s been a while since I’ve done a proper radio based post, so it’s a bit of a shame that I have to start off with a rant, but it’s required in this case.

One of the local 70cm repeaters, GB3WP seems to have many problems. The largest one seems to be G6YRK, the repeater keeper.

I had heard rumours of the repeater suddenly going off air getting switched off when either an M3/M6 or 2E0/2E1 was using it. At the time I thought no fellow ham could be quite that petty.

What callsign I or anybody else has should not make a shred of difference whether we should be allowed on the air or not. I personally keep my operating standards as high as possible, way above and beyond what Ofcom stipulates in the licence terms, as it’s part of making the hobby enjoyable for everyone. Seems that not everyone feels the same (in my experience, the older generation of hams, some of whom believe that the tests these days are far too easy, etc, etc).

Then I got proved wrong.

I was doing some handheld radio testing with M3HHY over at Distant Signal Radio on GB3WP, as at the time GB3MR was having some issues with the local pirate (see my previous posts for more info on that prat).

Within a couple of minutes of us establishing a QSO, the repeater suddenly stopped responding. After trying to get back in for a good 15 minutes, it came back on air again.
The instant we gave our callsigns, off it went, into the ether. No response.
This behaviour continued for nearly an hour, and after trying to contact YRK directly, we gave it up as a bad job, with quite a bit of pissed off added into the mix.

If I’d not heard stories of the repeater being turned off when the “wrong people” are using it, I might have put it down to dodgy repeater equipment, but even that didn’t make sense, as it had a definite pattern.
We both fired off an email to the Repeater Keeper, only to get no response from that either (surprise, surprise).

That was the last time I personally attempted to make use of GB3WP.

Until I was given an audio clip of G6YRK in action this evening.

Seems that not even M0 calls are immune from being wiped off the air by GB3WP. Chris, M0OGG, has apparently also had this issue with the repeater. Lucky for him, he had the opportunity to speak to the keeper directly about what went on.

Here’s the audio, I’ll pick each part out & go into a few opinions/observations below.

So, Chris (M0OGG) has asked a simple question, and been met with hostility. Dick Move Number 1.

YRK is clearly reluctant to go into “detail” on the air. Probably because he’s talking complete shite. Only when Lewis (M3HHY) joins in with a slightly more defensive tone does Steve (G6YRK) actually say what Chris has been “reported” for.

After all that it seems that an accusation of keying over other repeater users is the bullshit line of the day. (For the record, I know Chris, he’s not the type of person to key over another radio user, that behaviour in of itself is idiotic).
Apparently he has witnesses to this action, and he’s insisting that others were also involved. Not to mention the fact that RDF has been done on (I’m assuming) all of these “offenders”. G6YRK must have quite the army of hams with lots of spare time.
I’m not sure who the other station is, as he doesn’t give a callsign.

As Lewis jumps in & comments, the Repeater Keeper should be saying something to users he suspects of this kind of thing, in my opinion.

The real reason, of course, that he keeps turning the repeater off when others are using it is that he’s a passive-aggressive vindictive moron.

Surprise, surprise, he can’t remember the “exact date”, (because it never actually happened), it’s just “the other day, somebody did it”. Yeah, great evidence there Steve, because apparently the only person around at the time was Chris. How can he know this? When a repeater has a coverage area as wide as GB3WP, this guy is claiming that he knows that only a single person is listening? No, I think it’s bullshit too.

GB3WP Coverage Map
GB3WP Coverage Map

For reference, here’s the coverage map of the repeater. Steve G6YRK must be bloody psychic to make such a comment.
He then mentions a “friend” of Chris, but again refuses to give any names. Again I’m calling bullshit.
Swifty following this he goes into full kick-my-toys-out-of-the-pram mode because he’s been openly challenged.
While he’s correct in his statement that he can do as he pleases with the repeater, it’s not very good form to just switch the thing off when licenced users are having a perfectly valid QSO. If he doesn’t like people using the repeater, he should turn it off permanently & remove the listing from the repeater group.

After this, Steve makes the comment that he knows nothing of the repeater going off, as he’s been out all night. He mentions his Repeater Stasi again, and then makes a partial retraction of his previous statement, now that it “might” not have been Chris previously. Well Steve, we’re finally getting towards something that resembles truth. You’ve got absolutely no idea who is “keying people out”, if it’s even happening at all. So much for “having people all over the place” listening to where transmissions are coming from.

After Chris confronts him again, he returns to the fallback of that as the NoV holder it’s his prerogative to be able to switch the repeater off whenever he pleases.

When confronted with the fact that people pay into the repeater group to help keep them running, he claims that Chris’ signal is breaking up. My arse. Every other station on the repeater can hear him fine.

There’s probably more to add to this, so if I get any more relevant information from other sources I’ll add on to the saga.

73s for now folks!

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17mm µMonitor

I’ve had a couple of viewfinder CRT modules for a while, & haven’t done much with them, so I decided to make a very small B&W monitor.

CRT
CRT

I ordered a small transparent ABS box when I made a large order with Farnell, that turned out to be just about the perfect size for the project! The CRT & PCB barely fit into the space. The face of the CRT itself is about 17mm across.

Module Installed
Module Installed

Here’s the main PCB & tube fully installed into the case. Barely enough room for a regulator left over!
Power is provided by a simple LM7809 IC to take a standard 12v input.

Module Rear
Module Rear

Rear of the case, showing the fit of the control board.

Connections
Connections

Here’s the back of the monitor, with the DC input jack & a 3.5mm 4-pole jack for audio & video. This allows simple connection to many devices, including the one I’ll use the most – the Raspberry Pi.

Completed
Completed

Completed monitor. Audio is handled by a very small 20mm speaker, currently mounted just below the CRT face.
Current draw from a 13.8v supply is 117mA.