Vertex VXR-7000U

[chasedog1]

Ok so this repeater on desk mode works as it should. On repeat mode it will repeat the broadcast, the repeater tail ends then when it does it still transmits but does so with a squeal and will not stop unless the power is turned off. Any suggestions of where to start ?

[tweiss3]

The internal oscillator on the VXR7000 never turns off, it is always on when in repeat mode. This helps reduce keyup/warm up time. Get a few hundred feet away and see if you are still experiencing the same "issue". Your HT will always pickup the internal oscillator if you are in close proximity to the unit.

[chasedog1]

its definitely not that. I can be in the car a mile away and still get a sequel after the tail ends. I can even hear it through the  speaker on the repeater. it will happen even with the duplexer removed and two separate antennas. It does it with or with out the duplexer.

[Sshannon]

7 hours ago, chasedog1 said:

Ok so this repeater on desk mode works as it should. On repeat mode it will repeat the broadcast, the repeater tail ends then when it does it still transmits but does so with a squeal and will not stop unless the power is turned off. Any suggestions of where to start ?

Does it sound like feedback?

[chasedog1]

yes it sounds like a feedback squeal and as soon as I push the repeater button to turn the function off it stops transmitting.

[Sshannon]

29 minutes ago, chasedog1 said:

yes it sounds like a feedback squeal and as soon as I push the repeater button to turn the function off it stops transmitting.

I wonder if the connections within the repeater have sidetone from the transmitter side going back into the repeater. 

[chasedog1]

lost me on that one, you are the PE I am just a hobbyist

[Sshannon]

9 minutes ago, chasedog1 said:

lost me on that one, you are the PE I am just a hobbyist

I apologize. I was just wondering if some audio (I guess it could be RF also) is somehow being routed back from the transmitter to the receiver side of the repeater, where it would be picked up and sent to the transmitter as feedback. I know nothing about that specific repeater so my speculation is probably BS anyway.

 

[chasedog1]

Well you know way more than I do about it, its really frustrating me to the point I am ready to give up after putting a ton of money into everything ... I just don't know where to start testing to see whats wrong.

[Sshannon]

15 minutes ago, chasedog1 said:

Well you know way more than I do about it, its really frustrating me to the point I am ready to give up after putting a ton of money into everything ... I just don't know where to start testing to see whats wrong.

Look at this that I found on ehams:

https://www.eham.net/reviews/view-product?id=3650

In 2007 our repeater site was apparently struck by lightning, resulting in damage to our VXR-7000 repeater unit. It was returned to Yaesu for repair.
Upon the repeater’s return we became aware that the unit was not as sensitive as it had once been. Initially we put this down to band conditions and bided our time. When things did not improve, we began testing our whole repeater installation. We had our duplexer professionally checked out by a fellow ham with access to professional test equipment. The duplexer is totally up to spec.
We had the repeater checked by similar test equipment and it was found to be in order. 
Yet we found the following to be the case:
• reception from our fringe areas of the repeater coverage was poor at best, with stations that once easily held the repeater no long able to do so.
• a low-volume hum appeared on the background of the repeater output. The hum was not present on the input signals to the repeater.
• there was a click generated at the end of each relayed transmission. This was not previously present.
As the equipment seemed to test out we reasoned that the problem must be in our cable interface. 
Accordingly we replaced our repeater/duplexer cables with new RG214 cables with N connectors. These were fabricated by The Wireman in South Carolina. These new cables replaced our original RG8 cables which have PL 259 connectors on one end. We used N adapters to connect to the VRX 7000. 
We again contacted the Yaesu Service Department and were advised that 
“In December 2007 we identified a problem in the TX Unit that caused oscillations and feedback when certain duplexers were connected to the repeater. This would cause a 'desense' like problem in the repeater. This occurred within certain serial numbers or when an older unit had the PA Unit replaced with the new PA Unit (as yours was).”
“I have attached the technical bulletin describing the fix. We would of course be happy to install this for you here but considering the shipping costs, you may want to apply the fix locally. It is a single component change (adding a capacitor). Please take a look at the Technical Bulletin and let me know what you decide.”
After reading the bulletin we had Yaesu send us the capacitor required. We installed it and our repeater is now working flawlessly. The fringe area coverage is, if anything, superior to its previous good state.
Should this seem to be your situation, we suggest you contact Yaesu and request Service Bulletin TB0711-1A. If this does not work out for you, please email either Jerry (VE5DC) at jkdixon@imagewireless.ca
or Slater (VE5OA) at s.tubman@sasktel.net

 

[chasedog1]

thank you I will check the caps  and replace as necessary..

[Sshannon]

19 minutes ago, chasedog1 said:

thank you I will check the caps  and replace as necessary..

I didn’t read the technical bulletin. Does it sound like it could be related?

[chasedog1]

it could be but it seems it has to do with receiver desence but its worth a shot, I will look farther to see if my serial-lot number is effected. 

[tweiss3]

Also unplug the microphone from the repeater and see if that changes anything. 

[chasedog1]

2 hours ago, tweiss3 said:

Also unplug the microphone from the repeater and see if that changes anything. 

It still does the same thing. I am going bald pulling my hair out trying to figure this out...

[Radioguy7268]

Try to remove or de-activate all other channels besides the single active repeater channel. Make sure you're not scanning.

Set repeater hang time to zero.

You can also try to change to a "split PL"  - using different PL/DPL codes for Transmit & receive.  That should tell you if there's something internally generated on the transmit side that's keeping the repeater keyed.

Without a service monitor and some RF specific test equipment, you're limited to basic troubleshooting methods. Try to eliminate potential trouble points one by one until you get it done.

[chasedog1]

Thanks for the reply Radioguy, I'll give that a shot in the next few days. All I have is a VNA but I don't think that will help much.

[chasedog1]

I tried using just one channel and then putting the original code plug i was given when I got the repeater and it still hangs on but now with static that's choppy. I tuned a new duplexer and still the same thing happens. Anyone suggestions on where to send a sick repeater near Delaware ? I did see one place in North Jersey, anyone have any suggestions on an affordable repair location ? Thanks everybody for the help....

[gortex2]

Talk to Demlarva Communications in New Castle. They are a MSI shop and should be able to diagnose the issue pretty quickly. There is also Magmum in Dover area but never dealt with them. 

[chasedog1]

1 hour ago, gortex2 said:

Talk to Demlarva Communications in New Castle. They are a MSI shop and should be able to diagnose the issue pretty quickly. There is also Magmum in Dover area but never dealt with them. 

oh nice, I'll look them up 2day. Thank you.

[chasedog1]

The unit has been taken to Delmarva Communions and I am waiting on a diagnosis. Hopefully it will be repairable for a reasonable cost, I like the fact I can have a repeater to let everyone use. I have thousands in tower, hardline and antenna no to mention the the unit and a bunch of mobiles and ht's..hope it's going to be worth repairing for all to use.