i have a robyn 510d am and usb seem to work like they should but when i switch to lsb it will work one second and the next it wont the rx seems to dim down a little and when it does there is no tx or very little but when the rx comes back im getting almost 20 watts same as usb am gets a little over 10 watts
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robyn 510d no tx low rx on lsb
- Thread starter tyler sherwood
- Start date
Shadetree Mechanic
Delaware Base Station 808
Welcome Tyler, if it works in USB and is intermittent in LSB then I would suspect the mode switch. Try cleaning the contacts on the USB, LSB, AM switch and see if that works. If that doesn't fix it then maybe the capacitors need to be replaced.
Chris
Anyway to bypass the mode selector switch. What capacitors can i use to replace the tantalum capacitors i know c179 is a 2.2uf but i dont know if the rest are the same?
The important spec for replacing C179 is the voltage rating. The factory used a 25-Volt part. Works fine until the AM modulation limiter gets turned up. Causes the capacitor's voltage rating to be exceeded, and it fails as a dead short.
A part rated for 35 Volts or more is what's needed. A tantalum cap is probably best. An aluminum electrolytic will probably work just fine.
Other folks report that just leaving it out is okay. Don't know, we always just replace it.
The symptom sounds like the LSB carrier crystal X2 might be showing its age. Quickest way to be sure is to simply swap X1 and X2. Should be in sockets, so no soldering iron needed. If the problem moves to USB mode now, the LSB crystal X2 needs to be replaced. And if the problem is STILL in LSB, the crystal is probably okay, and some other component is causing the fault.
73
A part rated for 35 Volts or more is what's needed. A tantalum cap is probably best. An aluminum electrolytic will probably work just fine.
Other folks report that just leaving it out is okay. Don't know, we always just replace it.
The symptom sounds like the LSB carrier crystal X2 might be showing its age. Quickest way to be sure is to simply swap X1 and X2. Should be in sockets, so no soldering iron needed. If the problem moves to USB mode now, the LSB crystal X2 needs to be replaced. And if the problem is STILL in LSB, the crystal is probably okay, and some other component is causing the fault.
73
Yeah i think the crystal was the issue. My dad kept a bunch in a pyle feom old radios found one in there put it in thing has been going for 20 minutes with no issues whitch dident happen before im going to leave it on for about an hour or so if it dosent do it again i will say that was the problem. The c179 cap i know because i replaced one in my 139xlr but was wondering what the rateings are on the other tantalum caps in it were i cant find anything that says what the uf or volt rateings are for those
Ok so its been running about hour and a half now and no issues at all seems that was the issue. But is there a am crystal i can change out the recieve on am seems a little weak?
Dead receive can be a crystal. But weak receive probably not.
Alignment is the first diagnostic step when the receiver's sensitivity is not up to snuff.
73
Alignment is the first diagnostic step when the receiver's sensitivity is not up to snuff.
73