Telequipment D32

[bd139]

Ok so I was scrolling through eBay on the toilet this morning, like you do when you haven't eaten enough fibre for a couple of days, and guess what? I received a stupid low offer for a Telequipment D32. It's a very basic 10MHz dual trace scope which is by modern standards, not exactly that useful but it is extremely small, extremely portable (it is battery powered) and made out of entirely boring parts and has a mechanical construction which favours repair.

So £21 later and it's on the way.

Place your bets? Crusty NiCds that have destroyed it or something worse? Answers on a postcard.

There is a common failure mode with these that the NiCds go short and kill the mains transformer but being battery powered it's a fairly standard jobby which can be replaced easily as the whole thing is suitable for running on low voltage supplies (7.2v NiCd supply). Obviously there are some applications for it being a totally floating portable oscilloscope with a USB-C PD interface in the back. After all it runs on 14 watts which isn't a lot!

Propaganda attached

d32.jpeg

[Zenith]

I lost interest with Telequipment after the D43, of which I have three - and a D33, and an S51. All apart from one D43 worked the last time I checked - a long time ago.

Best of luck with this esoteric piece of TE which has doubtless found its forever home with a true enthusiast. I don't like the sound of those NiCads.

[tautech]

Prolonged chats about this on Discord over the last few hours.....
Manual:
https://w140.com/tekwiki/images/1/10/070-1797-00.pdf

[tautech]

Dusty but better pic from Tek wiki:

https://w140.com/tekwiki/wiki/Telequipm ... _d32_1.jpg

[tggzzz]

Best of luck with this esoteric piece of TE which has doubtless found its forever home with a true enthusiast.

True enthusiast, no doubt. But "forever home" and bd causes a cognitive dissonance

[Zenith]

"Forever home" is a somewhat schmaltzy term and a logical nonsense. It's probably fairer to say, "It's come to its last home." which is what my dad used to say when he saw me taking something to bits.

[bd139]

Final resting place

[tautech]

So you have it now and done some preliminary investigations but where are the pics ?

[bd139]

Yeah yeah yeah on it.

Ok so the D32 arrived nicely packaged. It's a very compact little battery powered scope. 10MHz dual trace. Nothing fancy but incredibly useful as they are light, don't take up a lot of room and of course can be easily floated (consider SMPS). Also 100% fully discrete with no fancy parts. Even the final amplifiers are half 2n3904's (!).

HP E3610A for scale

IMG_1706.jpeg

As expected it was full of crusty old NiCd cells. They were removed and discarded, soon to be taken to the tip for disposal properly of course.

IMG_1696.jpeg

Next trick was to get power into it. Looking at the schematic, this is simply a case of pulling the fuse, connecting 7.5V DC supply across two lines on the fuse and the battery and off you go.

NOTHING.

After scratching my head for a few minutes, I disassembled it further. This is a rather nice bit of design, unusual for TQ who usually provide you with a nightmare of short leads and soldering. It folds out into three directions, X, Y and I suppose Z/power.

IMG_1702 (1).jpeg

Some poking around and it was discovered that the power switch wasn't working. As for why, this is to determine yet but I suspect shitty soldering being TQ. Hooking up the power to the pins on the Z board was successful. Trace rotation off here - this does work but I didn't bother with it.

IMG_1704.jpeg

So far so good. For the next instalment I will be working out the DC jack connections on the back, fixing the power switch and seeing what else is up with it.

[Zenith]

I must say it's not a thing that would have tempted me, but each to his own. I had a quick look at the manual and it said the batteries were necessary as they were used as giant capacitors. Finding replacement NiCds may not be easy these days. They were very tolerant of charging regimes and in particular overcharging. Replacing them with NimH or Li-ion cells may not be straightforward.

I'm sure you have plenty of experience of festering NiCds. I've found leaking batteries can contaminate switches sometimes, even if there's no obvious leakage which has spilled onto them. That may explain the mains switch problem.

The story I heard was that Tek wanted to enter the educational market, but they couldn't bring themselves to produce an oscilloscope at a low enough price to be competitive, so they bought Telequipment, which had been a fairly successful company, and had no problems at all with "value engineering".

[tggzzz]

I must say it's not a thing that would have tempted me, but each to his own. I had a quick look at the manual and it said the batteries were necessary as they were used as giant capacitors. Finding replacement NiCds may not be easy these days. They were very tolerant of charging regimes and in particular overcharging. Replacing them with NimH or Li-ion cells may not be straightforward.

That's my experience with the (early 70s) Tek 1502.

That has a weird {s]and wonderful[/s] PSU, based on a PUJT. While it delivers 0.1C charging current, it is highly pulsed. Eventually Tek added a service note not to leave them charging for more that 16 hours - in addition to the operating note that they should be recharged monthly.

[bd139]

I must say it's not a thing that would have tempted me, but each to his own. I had a quick look at the manual and it said the batteries were necessary as they were used as giant capacitors. Finding replacement NiCds may not be easy these days. They were very tolerant of charging regimes and in particular overcharging. Replacing them with NimH or Li-ion cells may not be straightforward.

I'm sure you have plenty of experience of festering NiCds. I've found leaking batteries can contaminate switches sometimes, even if there's no obvious leakage which has spilled onto them. That may explain the mains switch problem.

The story I heard was that Tek wanted to enter the educational market, but they couldn't bring themselves to produce an oscilloscope at a low enough price to be competitive, so they bought Telequipment, which had been a fairly successful company, and had no problems at all with "value engineering".

Surprisingly perhaps, a lot of TQ stuff made it into well respected Tektronix products. The entire 5000 series Tektronix units were derived from the D83/DM64 chassis and design. As was the TM500 chassis. And they did the design and production of the 2200 series of scopes. Ergo, it wasn't such a bad idea after all

As for the NiCd cells - they are completely gone. Good point about the switch but I think this is likely shitty soldering. TBD of course.

The intent with this is to "modernise" it. The original design is a 7.5V 4Ah (30Wh) supply which gives 3-4 hours of operation. We can do better than that now. So what I am probably going to do is the unthinkable and eviscerate the entire mains front end from it right up to the 7.5V DC supply. This of course removes a lot of weight as well. It doesn't have a line trigger so this is no loss in that department! In place of the original will be a lithium ion pack, BMC, USB-C charger and boost converter arrangement, the mains hole being replaced with the BMC USB-C input and the multi-colour charge LED brought out to the front panel to replace the existing LED.

[mnementh]

Give me some dimensions and I'll design/print you a filler plate.

mnem

[tautech]

.............
The intent with this is to "modernise" it. The original design is a 7.5V 4Ah (30Wh) supply which gives 3-4 hours of operation. We can do better than that now. So what I am probably going to do is the unthinkable and eviscerate the entire mains front end from it right up to the 7.5V DC supply. This of course removes a lot of weight as well. It doesn't have a line trigger so this is no loss in that department! In place of the original will be a lithium ion pack, BMC, USB-C charger and boost converter arrangement, the mains hole being replaced with the BMC USB-C input and the multi-colour charge LED brought out to the front panel to replace the existing LED.

Pleased to have sown this seed....looking forward to your improvements.

[bd139]

.............
The intent with this is to "modernise" it. The original design is a 7.5V 4Ah (30Wh) supply which gives 3-4 hours of operation. We can do better than that now. So what I am probably going to do is the unthinkable and eviscerate the entire mains front end from it right up to the 7.5V DC supply. This of course removes a lot of weight as well. It doesn't have a line trigger so this is no loss in that department! In place of the original will be a lithium ion pack, BMC, USB-C charger and boost converter arrangement, the mains hole being replaced with the BMC USB-C input and the multi-colour charge LED brought out to the front panel to replace the existing LED.

Pleased to have sown this seed....looking forward to your improvements.

Yes a good idea that!

[tautech]

.............
The intent with this is to "modernise" it. The original design is a 7.5V 4Ah (30Wh) supply which gives 3-4 hours of operation. We can do better than that now. So what I am probably going to do is the unthinkable and eviscerate the entire mains front end from it right up to the 7.5V DC supply. This of course removes a lot of weight as well. It doesn't have a line trigger so this is no loss in that department! In place of the original will be a lithium ion pack, BMC, USB-C charger and boost converter arrangement, the mains hole being replaced with the BMC USB-C input and the multi-colour charge LED brought out to the front panel to replace the existing LED.

Pleased to have sown this seed....looking forward to your improvements.

Yes a good idea that!

Further thoughts to ponder on:
Scope ON = solid color LED and/or flashing if being charged.
Scope OFF but charging = LED in a flashing state, changing to a different but solid color when fully charged.

[bd139]

Pleased to have sown this seed....looking forward to your improvements.

Yes a good idea that!

Further thoughts to ponder on:
Scope ON = solid color LED and/or flashing if being charged.
Scope OFF but charging = LED in a flashing state, changing to a different but solid color when fully charged.

It's getting whatever the shite charge controller does out of the box

[tautech]

Yes a good idea that!

Further thoughts to ponder on:
Scope ON = solid color LED and/or flashing if being charged.
Scope OFF but charging = LED in a flashing state, changing to a different but solid color when fully charged.

It's getting whatever the shite charge controller does out of the box

Then you know what worthwhile features to look for in a charge controller.

[tggzzz]

Yes a good idea that!

Further thoughts to ponder on:
Scope ON = solid color LED and/or flashing if being charged.
Scope OFF but charging = LED in a flashing state, changing to a different but solid color when fully charged.

It's getting whatever the shite charge controller does out of the box

The possibility of shite controllers are one reason I don't like leaving low-end equipment containing Li batteries charge unattended.

[bd139]

Further thoughts to ponder on:
Scope ON = solid color LED and/or flashing if being charged.
Scope OFF but charging = LED in a flashing state, changing to a different but solid color when fully charged.

It's getting whatever the shite charge controller does out of the box

The possibility of shite controllers are one reason I don't like leaving low-end equipment containing Li batteries charge unattended.

A wise move generally. I am less worried about the controllers than the cells themselves. The cells can look perfectly normal to a charge controller even if they are pissing fire out of one end.

[tggzzz]

It's getting whatever the shite charge controller does out of the box

The possibility of shite controllers are one reason I don't like leaving low-end equipment containing Li batteries charge unattended.

A wise move generally. I am less worried about the controllers than the cells themselves. The cells can look perfectly normal to a charge controller even if they are pissing fire out of one end.

Quite possibly.

I was presuming, possibly optimistically, that the equipment had started with decent cells. Even those could be compromised by a shite controller.

[bd139]

The possibility of shite controllers are one reason I don't like leaving low-end equipment containing Li batteries charge unattended.

A wise move generally. I am less worried about the controllers than the cells themselves. The cells can look perfectly normal to a charge controller even if they are pissing fire out of one end.

Quite possibly.

I was presuming, possibly optimistically, that the equipment had started with decent cells. Even those could be compromised by a shite controller.

Oh no it'll be shite cells and a shite controller. Is it possible to get anything else? I mean even the old SLA chargers were shite and so were the SLA batteries.

Much prefer mains. On that I must replace this bloody laptop with a desktop at some point. Infernal battery scares me in it (mostly from the longevity perspective).

[tggzzz]

A wise move generally. I am less worried about the controllers than the cells themselves. The cells can look perfectly normal to a charge controller even if they are pissing fire out of one end.

Quite possibly.

I was presuming, possibly optimistically, that the equipment had started with decent cells. Even those could be compromised by a shite controller.

Oh no it'll be shite cells and a shite controller. Is it possible to get anything else? I mean even the old SLA chargers were shite and so were the SLA batteries.

Much prefer mains. On that I must replace this bloody laptop with a desktop at some point. Infernal battery scares me in it (mostly from the longevity perspective).

Laptops worry me w.r.t. ergonomics. Buggered wrists and backs.

I have an approx 15yo Samsung netbook that still holds a usable charge.

[bd139]

Quite possibly.

I was presuming, possibly optimistically, that the equipment had started with decent cells. Even those could be compromised by a shite controller.

Oh no it'll be shite cells and a shite controller. Is it possible to get anything else? I mean even the old SLA chargers were shite and so were the SLA batteries.

Much prefer mains. On that I must replace this bloody laptop with a desktop at some point. Infernal battery scares me in it (mostly from the longevity perspective).

Laptops worry me w.r.t. ergonomics. Buggered wrists and backs.

I have an approx 15yo Samsung netbook that still holds a usable charge.

Yes mine is permanently connected to my monitor and I have separate keyboard and mouse which is on a proper desk with a proper chair and foot rest. Hence why I need to replace it. It's mostly being used as an emergency backup should the power go out. But it turns out I don't give a shit and would rather just amble off and go read a book if that happens.

I do have a pretty hefty PC desktop as well but, urgh, it's a PC.

[mnementh]

I sortof assumed you'd just steal a battery out of one of your Winblows laptops from work to bust up for decent quality cells...

mnem