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Author Topic: Any FT-901 gurus out there?  (Read 10995 times)
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The Slab Bacon
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« on: August 10, 2006, 08:24:43 AM »

I recently picked up a FT-901D at the berryville fester for a very cheap price. I knew it had "issues" and fully expected to spend some bench time on it. I have resolved all of the issues but one. If anyone out there has had this problem, a point in the right direction would surely be appreciated.

It is now working fairly well and has even seen some PW duty on 3.880. One weird problem still perplexes me. (This is the first ricebox that I have owned.) When you hit the PTT or switch from rx to tx the display drops 300Hz in readout. This is with the R.I.T. turned off. I can compensate for it by setting the T.I.T. to the desired frequency, but this annoys me. I kinda think this may be a simple alignment / adjustment issue. (I havent determined if the actual tx freq is changing or just the display yet.) The manwell is a bit vague in this dept. I have adjusted the R.I.T. frequency shift ac\djustment per the manwell, but still no help.

I still feel that this is a simple adjustment that I dont know about. Before I start dismembering it lookiing for a problem that may not be a problem, I figgered that that it cant hurt to seek someone who may have also had this problem.

I am also looking for an AM filter for it. Any insight into this problem will be greatly appreciated!!
                                                      The Slab Bacon
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Ed KB1HVS
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« Reply #1 on: August 14, 2006, 05:42:47 PM »

Try to get in touch with Carol W4CLM. She may be able to steer you to a filter and give some insight to your problem.  She has helped me out with my FT 101E/EE/B and is as close to a Yaesu guru I can think of.

http://foxtango.org/FT901/FT-901-902%20Web%20Page.htm

http://foxtango.org/foxtango001.htm
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The Slab Bacon
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« Reply #2 on: August 15, 2006, 07:40:21 AM »

thanks, ED! That is a pretty kool site. Lots of really good info. I will have to download and print lots of sctuff fot future references!
                                                                  The Slab Bacon
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Ed KB1HVS
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« Reply #3 on: August 15, 2006, 11:13:06 AM »

 Looks like INRAD may still have AM filters for the 901. Good luck with the rig!

http://www.qth.com/inrad/ft-901.htm
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Ed KB1HVS
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« Reply #4 on: August 15, 2006, 04:40:40 PM »

Well being the nosey  sort i did a little digging around and your problem might be this.....


radio drifts down in frequency replace regulator Q01 on rectifier c with 78o6 or a variable LM317 (I used LM317) Chris MW0HRD

 I gleaned this from the FT-901 Yahoo Group 
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The Slab Bacon
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« Reply #5 on: August 16, 2006, 08:13:12 AM »

Thanks, Ed,
                  Makes sense to me, beings the PLL is controled by a VCO. If the voltage changes, so does the frequency. The one thing I didnt do was to adjust the 6V regulated supply. I'll do some more tinkering. Sometimes it drops 100Hz, sometimes 200Hz and sometimes 300Hz. Never more than 300Hz when you transmit. Also the display frequency will change + 100Hz for no apparent reason. This could be the regulated voltage moving around. I'll dig deeper. thanks again.

                                                           The Slab Bacon
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The Slab Bacon
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« Reply #6 on: August 17, 2006, 08:12:47 AM »

Ed,
     I found the problem last nite. I adjuster the regulator, no help. It was holding steady and not fluctuating. Even changing the voltage setting did not change the freq.  I started the old wiggling and tapping trick, and found that if you tapped the PLL card the freq would wiggle a few hundred Hz. Pulled the card out and cleaned the card edge connector; VOILLA problem gone!! Its now steady as a rock.

That card is in a metal box and a real pain in the a$$ to get out. All is well that ends well. Many thanks for the insight and help. I like the Fox Tango website. Now I have to justify the cost for tha AM filter. At $105 it is a little tough to swallow after only paying $40 for the whole radio! Go figger!!
                                                             The Slab Bacon
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Ed KB1HVS
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« Reply #7 on: August 17, 2006, 11:18:32 AM »

 Ya know I was going to ask you if you had pulled out   cleaned and reinserted the boards but I thought maybe you already did that. That's cool you got it running and for 40 bucks that's even better. I just got a Yaesu FT 101E for $150.00 that was suppose to have been dead but after just cleaning it up and replacing the ant relay in the PA compartment it came to life. This one came with the AM filter so I'm going to (try) Wink do the famous AM mods. $105.00 for a filter is  a lot but if the rig is in good shape it may be worth it. Ask around on the Fox Tango site and if you become a big enough pain maybe someone there can hook you up for a filter. I like the older Yaesu rigs and I have heard a few FT-901s on AM and they didn't sound half bad. Hope to hear you on the air with it. I've heard you quite a bit but it seems I never can get on these days. 73 Ed HVS Smiley
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The Slab Bacon
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« Reply #8 on: August 17, 2006, 01:29:43 PM »

Ed,
     I had many problems with a similar rig. I have an old FT-221 analog 2 meter all mode.(looks like an FT-301) It also wasnt working when I got it many years ago. I have to pull out the cards and clean the connectors every 5 years or so. Analog or not I love that radio. The FT-901 is similar in basic construction, I should have figgerd the card edge connectors would bite me.

I puled out all of the cards on the left side of the rig, but the PLL card is in a shielded box screwed to the chassis at the bottom. That board and the one next to it are tough to get at the screws that hold them down. You know whar happenz when one assumes!! Bit again!! Grin Grin
                                                        The Slab Bacon
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Ed KB1HVS
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« Reply #9 on: August 18, 2006, 10:39:07 AM »

 Yes I certainly do!   Grin
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