No I have not done any of the low distortion mods to the 502¡¯s in the lab but I am now curious as to what these entail. I popped mine open tonight and found I used a 10K resister to calm the LED down and make it liveable and not eye searingly green. Do you have a link to the low distortion information? ? Zen ?
toggle quoted message
Show quoted text
From: [email protected] < [email protected]> On Behalf Of Radu Bogdan Dicher Sent: Monday, September 26, 2022 9:58 PM To: [email protected]Subject: Re: [TekScopes2] SG502 Repair ? How could I miss it: 7220 bulb, 26mA?@ 18V...? ? On Mon, Sep 26, 2022 at 6:20 PM Radu Bogdan Dicher via <vondicher=[email protected]> wrote: One concern I do have with my grain of rice bulb is it wants 60mA. The entire plugin I recall reading somewhere - can't find it now - needs 70mA, so I'm a bit weary of raising the current through the pass transistors quite a bit. True, I don't know the draw of the original bulbs. Knowing the specs of the original bulbs would help quite a bit. ? On Mon, Sep 26, 2022 at 5:15 PM Radu Bogdan Dicher via <vondicher=[email protected]> wrote: Zen - glad to see you here! Yes, a very cute unit. I'm looking forward to checking it closer against?my instrumentation - such as looking at its distortion through the AP S1. Also, checking the levels and all that (though this far it looks absolutely dead on). Calibrate it, if it needs it. Have you done the?"low distortion mods," I'm curious?....? The LED suggestion is a very good idea, I may go that way.? Glenn - no, the bulb looks like a legged... whatchumacallit - "grain-of-rice" bulb? I do have some Radioshack #7219s, though I may have to change the series?resistor if I use one of those. They do have 10,000hrs average life, so not a bad option.? ? Does it look like this?
Glenn On 9/26/2022 9:28 AM, Radu Bogdan Dicher wrote: Hi all, Does anyone have information on the correct power lamp for this unit? I can't find that info - all I can find in the manual is it being a "DS346." ? On Sun, Sep 25, 2022 at 10:12 PM Radu Bogdan Dicher via <vondicher=[email protected]> wrote: Well, I had no symptoms yet to?file, as until tonight I didn't get a chance to even plug it in. Visually, the only?clear issue I was seeing prior to tonight was the detached C160 (one leg was simply?mechanically loose). It was not trivial to resolder it, the short leg pretty much refused to take solder. But I ultimately won. ? I got it, I will not change this cap. Equivalents today seem to require an arm and both legs (except some surplus?places I know...). After taking care of C160, this outputs beautifully a very clean sine. The switches and pots are a bit in need of TLC, but other than that I'm very happy.? Thank you all for your input! ? On Sun, Sep 25, 2022 at 9:26 PM Froggie the Gremlin <jonpaul@...> wrote: what is symptom?
never replace timing caps
suspect the usual range switches, possible PS shorted rants.
Clean controls and trimmers
Should be simple to debug
Jon
-- ----------------------------------------------------------------------- Glenn Little??????????????? ARRL Technical Specialist?? QCWA? LM 28417 Amateur Callsign:? WB4UIV??????????? wb4uiv@...??? AMSAT LM 2178 QTH:? Goose Creek, SC USA (EM92xx)? USSVI, FRA, NRA-LM??? ARRL TAPR "It is not the class of license that the Amateur holds but the class of the Amateur that holds the license"
|
