Tektronix 7L12 Spectrum Analyzer Repair by vintageTEK Museum

[@elderbob100]

I love me some Tektronix oscilloscopes! 40 something years ago I was a microwave technician for a cable TV system. They provided a 465 scope for troubleshooting. I loved that scope! It would lock on to video and even had a Z axis input so you could make it into a very expensive black and white monitor. I got to where I could operate that thing in the dark by feel, upside down and backwards. Tektronix dominated the field of television.monitors. They used the Sony Trinitron CRTs for the picture monitors. All the old tape machines from RCA and Ampex came with Tektronix waveform, vector, and picture monitors as standard equipment. I found a 465 on eBay a couple of years ago for about a hundred dollars plus shipping. It must have been sitting on a shelf the whole time, because it is museum quality! It came with all the probes and accessories. The BNC connectors are very tight and the calibration is spot on. I got real lucky on that purchase. One of the great things about Tek scopes is their fit and finish. They look cool and spacy even when they are turned off! Very ergonomic designs and a pleasure to use. I look forward to seeing move of your videos. The Tektronix product line has not diminished with age. Keep up the good work!

[@ahmedalshalchi]

GOD bless you for all repairing and recovering of these precious jewels of golden age of electronics...

[@bobheadrick5228]

Wow - I had a 7L12 with a short on the -15V supply. It turned out to be the same cap as in the video here, C1382. It was an easy fix - once I pulled a leg of C1382 to confirm it was the issue the -15V short disappeared. I had not found anything in the service manual about even getting to the center section, this video was a great help.

[@keithnoneya]

Loved it thanks for the show guys. You guys should do some long term project videos on equipment restoration, like the 500 series and plug in or even some of the 400 series scopes. I know there's a large following of the 7000 series mainframe scopes like the 7904's etc. I know they're obsolete but I still love to just look at them. They are such a work of art with the digital readouts on the screen and the little square push buttons that lit up, they're just simply wonderful to look at in operation. Thanks again for sharing. Best Wishes & Blessings. Keith Noneya

[@AllElectronicsChannel]

Incredible piece of engineering!

[@ahmedalshalchi]

Not only but a piece of jewelry although you are new age Gregory my friend ...

[@silasmarner7586]

Nice. I think I mentioned to you one day that I had a Wiltron (ie Won't-tron) VNA that failed. It turned out a tantalum had one lead extending waaay out to it's intended trace. But it sagged a bit, and touched a lead it shou'n't have. When I got the old board back and the repaired board, you could see the little orange bead that leaked out on the bad tantalum, and they had put a little plastic sleeve where the lead had previously been dangling exposed to the trace below it on the repair.. So they KNEW it was a problem. They still charged me. Oh well such is life.

[@GrandsonofKong]

Thanks for the "how too" and hope you do more. ARRRG..those tear drop tantalum caps!!

[@StevePietras]

OMG! Getting the center module out is that easy? Wow. I have both the 7L12 (7603 chassis) and the 7L13 (7613 chassis). The 7L13 has an issue but now I know what to look for.

[@StevePietras]

Could you show how to clean the dB per division switches? Mine are dirty and need assistance going in and out.

[@cesargabrielachar4185]

good morning ! Merry Christmas I have a tektronix 7L12 with a 7603 monitor it was never repaired ... but it remains in a deposit. It turns on but it does not have a sweep if you can help me to put these marvels of an instrument into operation. Thank you !

[@cesargabrielachar344]

good night my good video! I also have the 7L12 and it has an integrated 155-003500, my question is ... which integrated circuit is its equivalent ... or replacement? greetings from Argentina!

[@cesargabrielachar4185]

good afternoon .. and happy new year 2022 ... I have a tektronix 7L12 and it has a quadruple orational integrated IC is Tek 155 0035 00 it is in circuit as U820 vertical output .. if you can help me to repair this instrument ... there is a replacement for IC U820 ??? greetings from Argentin

[@douro20]

Solid polymer capacitors may be good replacements where very low ESR is important.

[@marvintpandroid2213]

Tektronix: You were made as well as we could make you. Tantalum capacitors: But not to last . Tektronix: The light that burns twice as bright burns half as long - and you have burned so very, very brightly, Roy. Look at you: you're the Prodigal Son; you're quite a prize! Tantalum capacitors: I've measured... questionable things. Tektronix: Also extraordinary things; revel in your time.

[@silasmarner7586]

What's goin' on Bob! Jay Dub.

[@qwaqwa1960]

Great vid, but don't generalize about tant vs. Al-lytic ESR. Both can vary all over the place.

[@SolidStateWorkshop]

Yeah, agreed. Maybe was true back in the day when there was less variety of E-caps, maybe because switching power supplies hadn’t taken over the world yet.

[@SoddingaboutSi]

Those horrid little yellow tants are a nightmare.