TEK 7603 CRT replacement alternative - Page 1
Forum section: electronics / testgear

author: diyarpette
author_rank: Newbie
timestamp: January 26, 2023, 04:56:25 pm
content: Dear all,that's my first post here (after many months lurking). Good day from France to everyoneLastly, I have had the opportunity to puchase a tek 7603 mainframe with 2 vertical plugins and its time base, for 80 euros only which I assume is a fair price for a working unit.Alas, when it came to my house, the CRT has been broken during the shipmentI trust the vendor, he was reluctant to send it, due to the weigth and fragility, and it's me who convinced him to send it anyway. I took my share of responsabilities in the disaster and decided to pay and keep the scope, in the hope of finding a replacement CRT.Sure, I could certainly sale the plugins separately and recover my funds, but I prefer to repair it and add it to my small (mainly tek) scopes collection.It seems not so easy to find a T7400 CRT (P/N 154-0640-10) in France. Also, at this time I don't see much (in fact no one) CRT for sale on the bay... a few complete 7603 are offered for sale sometimes, but I don't see the point in buying another working unit and strip the CRT from it, or keep the first one for replacement parts only. I would like to resurect this one.Here is my (maybe silly) idea: I have sumbled upon an empty and cheap 5110 which bears a CRT with the same size that the one used in the 7603.I know this is not the same model, and the 5000 series is a low cost,low bandwith scope.I am also aware the the CRT used in the 5000 has no post deflection acceleration and is a different kind of animal than the T7400.Is it perfecly ridiculous to try to adapt a 5110 CRT in the 7603 ? Is it a lost battle in advance ?Should I wait, in the hope to find a genuine 7400 CRT ?RegardsPascal

author: perdrix
author_rank: Frequent Contributor
timestamp: January 26, 2023, 05:46:54 pm
content: I suggest you ask the folks on the Tekscopes (and Tekscopes2) mailing lists at groups.io:https://groups.io/g/TekScopeshttps://groups.io/g/TekScopes2You may find a member in France has exactly what you want.David

author: diyarpette
author_rank: Newbie
timestamp: January 26, 2023, 06:37:38 pm
content: Hello,thank you for your answer.I will do that.RegardsPascal

author: tautech
author_rank: Super Contributor
timestamp: January 26, 2023, 07:10:27 pm
content: Quote from: diyarpette on January 26, 2023, 04:56:25 pmAFAIK Telequipment D83 used the Tek 7603 CRT and to find one of them in the UK or EU might be very possible.Just looked up the PDF for the D83 mainframe I had and indeed the CRT is listed as a Tek 7400 with P31 phosphor.Look for d83mainV2.pdf online (15MB) and at the foot of P16 is the listing for the CRT V301.

author: jonpaul
author_rank: Super Contributor
timestamp: January 26, 2023, 07:19:13 pm
content: Bonjour cher Pascal :Une très mauvaise idée d'expédier des mainframes 7000 TEK ou des scopes CRT. L'emballage des boîtes et les vibrations les endommagent également.Ils doivent être récupérés en personne !SVP, Contacter moi via PM si vous préférez.Bien à vous, et Bon Chance!JonParis 6emeSi vous connaissez SN à Paris, il pourra peut-être vous aider à trouver une solution,

author: diyarpette
author_rank: Newbie
timestamp: January 26, 2023, 07:26:43 pm
content: Hello,Thank you.yes, I knew for the D83 (from tekwiki) but they are also scarce , and certailnly scarcer if broken, with a working crtPascal

author: diyarpette
author_rank: Newbie
timestamp: January 26, 2023, 07:27:31 pm
content: Bonjour Jon;ok je vous contacte en pm :-)MerciPascal

author: tautech
author_rank: Super Contributor
timestamp: January 26, 2023, 07:38:32 pm
content: Quote from: jonpaul on January 26, 2023, 07:19:13 pmThis is an English forum so why do you need reply to your French countryman that can apparently write and read English just fine ?For the rest of us you said:Hello dear Pascal:A very bad idea to ship 7000 TEK mainframes or CRT scopes. Packing boxes and vibrations also damage them.They must be picked up in person!Please contact me via PM if you prefer.Yours, and Good Luck!JonParis 6thIf you know Stephen N in Paris, he may be able to help you find a solution,

author: MadTux
author_rank: Frequent Contributor
timestamp: January 26, 2023, 07:58:36 pm
content: Especially Tek7603.Has some weird ceramic/glass mixed CRT, front part ceramic, electron gun assembly from glass and it usually breaks where ceramic front piece is connected to electron beam assembly.Better don't ship them!

author: David Aurora
author_rank: Frequent Contributor
timestamp: January 26, 2023, 11:02:30 pm
content: Contacthttps://vintagetek.organd see if they can help. The managed to fix me up with a CRT for a 576 last year, an apparently impossible feat. Really nice people to deal with.

author: jonpaul
author_rank: Super Contributor
timestamp: January 27, 2023, 02:21:36 am
content: Actually replacement of the CRT is not a trivial proceedure....High voltage, implosion protection, complete CRT circuit,H and V calibration.I recall the mainframe cal requires the standardizer cal plug-in.Steep learning curve.may be easier to find anothern7xxx mainframe.Jon

author: H713
author_rank: Regular Contributor
timestamp: January 27, 2023, 05:11:58 am
content: Don't waste your time trying to shoehorn a 5110 CRT into a 7603. Two very different scopes, with very different CRTs.Replacing a CRT already is something of a pain, because you pretty much have to recalibrate the entire scope. Replacing it with a significantly different CRT gets more into the territory of designing a new scope. Since the 5110 (and its tube, for that matter) is something of a dog, you'll still end up with a dog when you're done.

author: diyarpette
author_rank: Newbie
timestamp: January 27, 2023, 07:15:41 am
content: Dear all,thank you for your wise advices.Although i am not a complete newbie (I have already fixed a few scopes, and am used to the voltage levels and implied risks among other things) I understand that trying to fit an other kind of tube would be creating a frankenscope,I have subscribed and posted to the tek groups, and will contact vintagetek, as recommended, hoping to get a replacement crt.thanks to everyone :-)Pascal

author: precaud
author_rank: Frequent Contributor
timestamp: January 27, 2023, 01:51:07 pm
content: Over the years I've parted out several 7603's, I'm sure I have a good crt, but I'm in the US.

author: diyarpette
author_rank: Newbie
timestamp: January 27, 2023, 04:57:50 pm
content: Quote from: precaud on January 27, 2023, 01:51:07 pmLucky youSo much easyer to find this kind of part here !

author: diyarpette
author_rank: Newbie
timestamp: February 11, 2023, 09:54:45 pm
content: Dear all,2 weeks ago, a member of the tekscopes@groups.io spotted a replacement crt on ebay.de and kindly sent an email to me . The price with shipping was really fair (~ 35 euros)The seller did not ship outside of germany, but per chance a friend on mine lives in Munich. I made the crt delivered to her, and she gave me the crt today, while she was on visiti in Paris !I have put the new crt in the scope, and it works prefectly (it is a 154-0841-00 that seemed intended for the R7603)I have now to recalibrate the scope.I am so happy !Many thanks to the members of this forum who pointed me to the tekcopes group !Pascal

author: DimitriP
author_rank: Super Contributor
timestamp: February 11, 2023, 10:07:57 pm
content: Few things beat the feeling of turning it on and working !!!For posterity, T7400 CRT (P/N 154-0640-10 ) can be replaced by 154-0841-00 intended for the R7603Enjoy your "new" scope