Monte....I had the 160's and I have bad news for you....you cant replace them and JTL told me that when the tube goes the circuit board goes and that the JTL 160's are basically disposable lights ....I had two of them, convinced me to never by another JTL product...mine were only a year old paid 450.00 for the set..boy did they see me coming!!!
Toss it and get an AB400 tubes are easily replaced and only 25-30 bucks!
250,000 flash life compared to JTLS 8,000...
Sorry about the bad news...but this was comfirmed when I contacted JTL CORP.