Texas Instruments OEM transistors

[RF Burn]

Hi,

I have recently come into possession of a quantity of NOS transistors, all T03 but marked with what appear to be OEM or 'house' part numbers, all but one type are of TI (Britain) manufacture and have large areas of glass insulation around the B/E pins suggesting they are high voltage (possibly Line Output) types.

TI
T6029,
T6070V,
T9013V,
T9038V,
T9051V,
0N188,
R2257,
R2265,
R2482,
R2540,
R2781

RCA
BRC116T

Does anyone have any info on these devices, just the commercial equivalent part numbers would be useful?

Adrian

[Herald1360]

The RCA one could be a British Radio Corporation own number.

[mhennessy]

The "T" types could be "Thorn". I've got a small number of them at home, which came from an uncle who worked for Ferguson/Thompson in Enfield back in the '80s, and I do have a record of the equivalents. I will endeavour to search them out this evening, and if any of mine match any of yours, I'll report back

[ukcol]

The only one I can identify is the R2482 which is listed in a 1976 Thorn guide to semiconductor replacement.

Their code TVT24 says this is a high voltage silicon NPN device. The BU205 is listed under the same code implying they are similar or equivalent transistors.

[dazzlevision]

Hello, I would say the Txxxx types are all specially selected for Thorn/Ferguson TV sets.

The BRC116T was also specially selected for Thorn (British Radio Corporation in those days) and used on the frame and sound board fitted in the Thorn 3000 and 3500 CTV chassis.

The ON188 is a specially selected Mullard type and was, I think, used in the line driver stage of the Philips G8 CTV chassis.

Regards,

Dazzlevision

[Bobdger]

The R2540 was used on the BRC 3000 / 3500 chassis.

[MALC SCOTT]

The R2540 was used in the Thorn 9000 chassis. The 3000/3500 used R2010, R2008.

[McMurdo]

Agree on the thorn selected transistors, they ring bells from my distant past...the sort of thing advertised in Television magazine by those full-page adverts from Sendz and Economic Devices.

In fact in the late 80's I was after a T(something)V transistor from an Ultra portable and when I rang Ferguson they just sent one for free.

[mhennessy]

Originally Posted by mhennessy

I will endeavour to search them out this evening, and if any of mine match any of yours, I'll report back

Sorry. Close, but no matches...

[RF Burn]

Thanks for the replies, I just thought that they might be useful for something if I knew what the characteristics were. If they are LOPT devices then I guess they are of the BU205/BU208 variety, probably not very useful for anything other than switch mode PSU's.

I suppose the 'OEM' part numbering was to lock service departments into buying replacement transistors from the TV manufacturer at inflated 'spares' prices.

Adrian

[Maarten]

If possible, I would like to see a picture of the ON type transistor or a transcription of any other codes that are on it. It was most likely manufactured by Philips/Mullard on customer spefications, but I have only seen ON-types made (for Philips) by others once, so if it is indeed a TI transistor that would be very interesting. My data collection on ON types and several other exotic Philips types can be found (in Dutch) at http://www.circuitsonline.net/forum/view/113864/

The OEM part numbering was at least partially, but I presume mostly, to prevent "hit or miss" replacements of transistors that were custom selected on one or more parameters (such as hFE) from normal production or even custom made variants on normal transistors.

For example the ON4673 line output transistor pair, consisted of what were basically 2 pieces of BU2508A binned and paired.

Most Sony repair technicians will also remember transistor choice in power supplies and line output stages being very critical sometimes.

[McMurdo]

I dont think there's anything vindictive about house part numbers. Many generic transistors for example have a large production spread of a particular parameter such as hfe as Maarten says or sometimes Vbe or Vceo, and setmakers ask the semi company for just those samples that satisfy their exacting needs and thus have a unique part number.

[G6Tanuki]

Regarding "specially selected" OEM house-branded transistors, there's a tale in "The Setmakers" about how when given the task of designing a colour TV, Thorn/Ferguson engineers went to the US to investigate how they were doing it over there.

They came back disillusioned at what they saw and convinced that a wholly solid-state colour-TV was the way they should go - however to do this they used a TI transistor for the EHT and line-output stages that was originally designed for a military radar and though these transistors were working within published performance-specs the transistors failed spectacularly-often.

Liaison with TI got them to tighten up the selection criteria for the transistors they supplied to Thorn/BRC/Ferguson for this particular application and the resulting Thorn/BRC "2000-series" TVs launched in 1967 were a success.

[RF Burn]

My apologies for the cynicism regarding private part marking, I was probably harking back to the days when RS/Radiospares only had their stock number printed on parts and refused to tell you who the manufacturer was or even reveal what the industry part number was (unless you asked the rep nicely!).

After spending most of my career in designing industrial electronic equipment where you would be sent back to the drawing board and told to do better if you presented a design which could not tolerate the parameter spread of the chosen devices, it is not easy to appreciate the different domestic design criteria...

Maarten, I have attached a picture of the 0N transistor for you. Definately a TI Bedford UK produced device, to me the first character looks more like the number zero rather than the letter O.

Adrian.

[McMurdo]

RS only had their stock number printed on parts and refused to tell you who the manufacturer was

Quite possibly so RS could swap and change the suppliers according to 'market forces'.

Maybe the Thorn 2000 'selected' radar transistor was the origin of the 'T' numbered LOP transistor?

[Herald1360]

Originally Posted by RF Burn

Maarten, I have attached a picture of the 0N transistor for you. Definately a TI Bedford UK produced device, to me the first character looks more like the number zero rather than the letter O.

Not sure the 1 isn't an I too. The two 8s and the 0 are a little shorter than the NI.

So ONI88. Probably no more helpful......

[Maarten]

It does look like a 0, so there may not be a Philips connection at all. I'm not sure. In any case, thanks for the picture and who knows... some information might turn up.

[paulsherwin]

Looks like zero NI eighty eight to me.